Reference

Crop phenology calendar

Every weather number is only meaningful against the crop's stage. A −2σ dry dekad during dormancy is noise; the same reading during grain fill is the story. This page fixes, for each of the 24 weather regions we publish, what the crop is doing in each month and which months actually carry yield risk.

It answers when. Its companion, Weather impacts by growth stage, answers so what — and keeps the two apart on purpose.

Yield-critical month — an anomaly here moves the crop Crop active, lower sensitivity Dormant, fallow, or out of season — not stated for that month

Critical months are also marked ◆ and set in bold, so the grid reads without color.

The grid United States (measured)Region detail How good is this?Weather impacts →

The grid

Pick a crop. Each region that grows it gets a card, and the months run down the card — so a card is one region's year, and scanning the same month down the page answers the question that matters when a single weather pattern spans several origins: who else is exposed right now.

Crop

Corn — 8 regions

ChinaNorth China Plain (winter wheat + summer corn)

Corn growth stage by month in China — North China Plain (winter wheat + summer corn). Cells marked critical are yield-determining.
Jan	—not stated
Feb	—not stated
Mar	—not stated
Apr	—not stated
May	—not stated
Jun	summer corn planting behind the wheat
Jul	vegetative
Aug	silking / pollination
Sep	grain fill → maturity
Oct	harvest
Nov	—not stated
Dec	—not stated

ChinaNortheast (corn & soybeans)

Corn growth stage by month in China — Northeast (corn & soybeans). Cells marked critical are yield-determining.
Jan	winter — no crop in ground
Feb	winter — no crop in ground
Mar	winter — no crop in ground
Apr	planting opens
May	planting → emergence
Jun	vegetative
Jul	silking / pollination
Aug	grain fill
Sep	grain fill → maturity — EARLY FROST RISK
Oct	harvest
Nov	post-harvest
Dec	winter — no crop in ground

ArgentinaPampas

Corn growth stage by month in Argentina — Pampas. Cells marked critical are yield-determining.
Jan	silking → early grain fill
Feb	grain fill
Mar	maturity, early harvest
Apr	harvest
May	—not stated
Jun	—not stated
Jul	—not stated
Aug	—not stated
Sep	early planting begins
Oct	planting → emergence
Nov	—not stated
Dec	silking begins

BrazilMatopiba

Corn growth stage by month in Brazil — Matopiba. Cells marked critical are yield-determining.
Jan	safrinha planting opens
Feb	safrinha planting
Mar	safrinha vegetative
Apr	safrinha flowering → grain fill
May	safrinha grain fill
Jun	safrinha maturity → harvest
Jul	safrinha harvest
Aug	—not stated
Sep	—not stated
Oct	—not stated
Nov	—not stated
Dec	—not stated

USDelta / Mid-South measured

Corn growth stage by month in United States — Delta / Mid-South. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground → planting
May	emergence
Jun	vegetative
Jul	silking / pollination → grain fill
Aug	grain fill
Sep	maturity / dry-down
Oct	harvest → post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USEastern Corn Belt measured

Corn growth stage by month in United States — Eastern Corn Belt. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting → emergence
Jun	vegetative
Jul	vegetative (canopy build) → silking / pollination
Aug	grain fill
Sep	grain fill (dent) → maturity / dry-down
Oct	maturity / dry-down → harvest
Nov	post-harvest fallow
Dec	post-harvest fallow

USNorthern Plains measured

Corn growth stage by month in United States — Northern Plains. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting → emergence
Jun	vegetative
Jul	vegetative (canopy build) → silking / pollination
Aug	grain fill
Sep	grain fill (dent) → maturity / dry-down
Oct	maturity / dry-down → harvest
Nov	post-harvest fallow
Dec	post-harvest fallow

USWestern Corn Belt measured

Corn growth stage by month in United States — Western Corn Belt. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting → emergence
Jun	vegetative
Jul	vegetative (canopy build) → silking / pollination
Aug	grain fill
Sep	grain fill (dent) → maturity / dry-down
Oct	maturity / dry-down → harvest
Nov	post-harvest fallow
Dec	post-harvest fallow

Wheat — 8 regions

ChinaNorth China Plain (winter wheat + summer corn)

Wheat growth stage by month in China — North China Plain (winter wheat + summer corn). Cells marked critical are yield-determining.
Jan	winter dormancy
Feb	dormancy → green-up
Mar	green-up → jointing
Apr	heading → flowering
May	grain fill — dry-hot-wind risk
Jun	harvest — harvest-window rain risk
Jul	—not stated
Aug	—not stated
Sep	—not stated
Oct	winter wheat sowing
Nov	emergence → tillering
Dec	entering dormancy

ArgentinaPampas

Wheat growth stage by month in Argentina — Pampas. Cells marked critical are yield-determining.
Jan	—not stated
Feb	—not stated
Mar	—not stated
Apr	—not stated
May	planting begins
Jun	planting → emergence
Jul	tillering
Aug	tillering → jointing
Sep	jointing → booting
Oct	heading → flowering
Nov	grain fill → early harvest
Dec	harvest

Australiaeastern wheat belt

Wheat growth stage by month in Australia — eastern wheat belt. Cells marked critical are yield-determining.
Jan	harvest tail → fallow
Feb	fallow
Mar	fallow — stored soil moisture accumulating
Apr	sowing on the autumn break
May	sowing → emergence
Jun	emergence → tillering
Jul	tillering
Aug	stem elongation / jointing
Sep	wheat: heading → flowering, grain fill opens wheat: spring frost risk window
Oct	grain fill
Nov	maturity → harvest
Dec	harvest

AustraliaWestern Australia wheat belt

Wheat growth stage by month in Australia — Western Australia wheat belt. Cells marked critical are yield-determining.
Jan	fallow
Feb	fallow
Mar	fallow
Apr	sowing on the autumn break
May	sowing → emergence
Jun	emergence → tillering
Jul	tillering
Aug	stem elongation / jointing
Sep	heading → flowering, grain fill opens
Oct	grain fill → early harvest
Nov	harvest
Dec	harvest tail

Francewheat

Wheat growth stage by month in France — wheat. Cells marked critical are yield-determining.
Jan	winter dormancy
Feb	dormancy → early tillering
Mar	tillering → stem elongation
Apr	stem elongation → booting
May	heading → flowering, grain fill opens
Jun	grain fill
Jul	maturity → harvest
Aug	harvest
Sep	post-harvest / land prep
Oct	sowing
Nov	emergence → tillering
Dec	entering dormancy

Indiawheat (rabi)

Wheat growth stage by month in India — wheat (rabi). Cells marked critical are yield-determining.
Jan	tillering → vegetative
Feb	heading → flowering, grain fill opens
Mar	grain fill — terminal heat risk
Apr	harvest
May	post-harvest
Jun	no wheat in ground — monsoon onset, kharif planting
Jul	no wheat in ground — monsoon
Aug	no wheat in ground — monsoon
Sep	no wheat in ground — monsoon withdrawal
Oct	land preparation
Nov	sowing
Dec	emergence → tillering

Russiawheat

Wheat growth stage by month in Russia — wheat. Cells marked critical are yield-determining.
Jan	winter wheat dormancy — winterkill risk
Feb	dormancy — winterkill risk
Mar	dormancy break / early green-up
Apr	green-up → tillering
May	wheat: stem elongation → heading, grain fill opens wheat: spring wheat sowing
Jun	winter wheat grain fill
Jul	winter wheat harvest opens; spring wheat grain fill
Aug	harvest; spring wheat fill → harvest
Sep	harvest tail; winter wheat sowing
Oct	sowing → emergence
Nov	emergence → entering dormancy
Dec	dormancy

Ukrainewheat

Wheat growth stage by month in Ukraine — wheat. Cells marked critical are yield-determining.
Jan	winter dormancy — winterkill risk
Feb	dormancy — winterkill risk
Mar	dormancy break / green-up
Apr	green-up → tillering
May	stem elongation → heading, grain fill opens
Jun	grain fill
Jul	harvest
Aug	harvest tail
Sep	sowing
Oct	sowing → emergence
Nov	emergence → entering dormancy
Dec	dormancy

Coffee — 7 regions

Brazilarabica

Coffee growth stage by month in Brazil — arabica. Cells marked critical are yield-determining.
Jan	cherry expansion → grain fill
Feb	grain fill
Mar	grain fill → early maturation
Apr	cherry maturation / ripening
May	harvest opens
Jun	harvest — frost risk window opens
Jul	harvest peak — peak frost risk
Aug	harvest tail; frost risk easing; pre-flowering water deficit
Sep	flowering — needs a rain trigger
Oct	flowering → pin-head set
Nov	flowering tail → cherry set
Dec	cherry expansion

Brazilconilon / robusta (ES, RO, BA)

Coffee growth stage by month in Brazil — conilon / robusta (ES, RO, BA). Cells marked critical are yield-determining.
Jan	cherry expansion → grain fill
Feb	grain fill
Mar	grain fill → maturation
Apr	harvest opens
May	harvest
Jun	harvest peak
Jul	harvest tail
Aug	post-harvest / pre-flowering deficit
Sep	flowering
Oct	flowering → set
Nov	cherry set
Dec	cherry expansion

Central Americaarabica (HN, GT, NI, CR)

Coffee growth stage by month in Central America — arabica (HN, GT, NI, CR). Cells marked critical are yield-determining.
Jan	harvest peak
Feb	harvest tail
Mar	flowering on the first rains
Apr	flowering → fruit set
May	fruit set → expansion
Jun	cherry expansion; leaf-rust pressure building
Jul	cherry development; rust pressure
Aug	cherry development; rust pressure
Sep	cherry fill; rust pressure peak
Oct	maturation
Nov	harvest opens
Dec	harvest

Colombiaarabica

Coffee growth stage by month in Colombia — arabica. Cells marked critical are yield-determining.
Jan	main harvest tail; principal flowering
Feb	flowering
Mar	flowering → fruit set; mitaca development
Apr	mitaca (fly crop) harvest opens
May	mitaca harvest
Jun	mitaca harvest tail
Jul	secondary flowering
Aug	main crop development
Sep	main crop maturation
Oct	main harvest opens
Nov	main harvest peak
Dec	main harvest

Ethiopiaarabica

Coffee growth stage by month in Ethiopia — arabica. Cells marked critical are yield-determining.
Jan	harvest tail
Feb	flowering on the belg rains
Mar	flowering
Apr	fruit set
May	cherry expansion
Jun	cherry development
Jul	cherry development
Aug	cherry fill
Sep	cherry fill → maturation
Oct	maturation; harvest opens
Nov	harvest peak
Dec	harvest

Indonesiarobusta (Sumatra / Lampung)

Coffee growth stage by month in Indonesia — robusta (Sumatra / Lampung). Cells marked critical are yield-determining.
Jan	cherry development
Feb	cherry development
Mar	cherry fill → early maturation
Apr	harvest opens
May	harvest building
Jun	harvest peak
Jul	harvest peak
Aug	harvest
Sep	harvest tail; flowering begins
Oct	flowering
Nov	flowering → fruit set
Dec	fruit set

Vietnamrobusta (Central Highlands)

Coffee growth stage by month in Vietnam — robusta (Central Highlands). Cells marked critical are yield-determining.
Jan	harvest tail; flowering begins — irrigation-dependent
Feb	flowering
Mar	flowering → fruit set
Apr	fruit set; rains onset
May	cherry expansion
Jun	cherry expansion
Jul	cherry fill
Aug	cherry fill
Sep	maturation; typhoon / heavy-rain risk
Oct	harvest opens — rain-at-harvest risk
Nov	harvest peak
Dec	harvest

Soybeans — 7 regions

ChinaNortheast (corn & soybeans)

Soybeans growth stage by month in China — Northeast (corn & soybeans). Cells marked critical are yield-determining.
Jan	—not stated
Feb	—not stated
Mar	—not stated
Apr	—not stated
May	planting
Jun	vegetative
Jul	flowering → pod set
Aug	pod fill
Sep	maturity — early frost risk
Oct	harvest
Nov	—not stated
Dec	—not stated

ArgentinaPampas

Soybeans growth stage by month in Argentina — Pampas. Cells marked critical are yield-determining.
Jan	pod fill
Feb	pod fill → maturity
Mar	maturity
Apr	harvest
May	harvest tail
Jun	—not stated
Jul	—not stated
Aug	—not stated
Sep	—not stated
Oct	—not stated
Nov	planting
Dec	planting → vegetative

BrazilMatopiba

Soybeans growth stage by month in Brazil — Matopiba. Cells marked critical are yield-determining.
Jan	pod fill
Feb	maturity → early harvest
Mar	harvest
Apr	—not stated
May	—not stated
Jun	—not stated
Jul	—not stated
Aug	—not stated
Sep	pre-planting, waiting on the rains
Oct	planting on the rains onset
Nov	vegetative
Dec	flowering → early pod set

USDelta / Mid-South measured

Soybeans growth stage by month in United States — Delta / Mid-South. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground → planting
Jun	emergence → vegetative
Jul	vegetative (canopy build) → blooming
Aug	pod set / pod fill
Sep	pod set / pod fill → dropping leaves / dry-down
Oct	dropping leaves / dry-down → harvest
Nov	post-harvest fallow
Dec	post-harvest fallow

USEastern Corn Belt measured

Soybeans growth stage by month in United States — Eastern Corn Belt. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground → planting
Jun	emergence → vegetative
Jul	vegetative (canopy build) → blooming
Aug	pod set / pod fill
Sep	pod set / pod fill → dropping leaves / dry-down
Oct	harvest → post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USNorthern Plains measured

Soybeans growth stage by month in United States — Northern Plains. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground → planting
Jun	emergence → vegetative
Jul	vegetative (canopy build) → blooming
Aug	pod set / pod fill
Sep	dropping leaves / dry-down
Oct	harvest → post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USWestern Corn Belt measured

Soybeans growth stage by month in United States — Western Corn Belt. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground → planting
Jun	emergence → vegetative
Jul	blooming → pod set / pod fill
Aug	pod set / pod fill
Sep	pod set / pod fill → dropping leaves / dry-down
Oct	harvest → post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

Winter wheat — 6 regions

USCentral & Southern Plains (HRW) measured

Winter wheat growth stage by month in United States — Central & Southern Plains (HRW). Cells marked critical are yield-determining.
Jan	winter dormancy
Feb	winter dormancy
Mar	winter dormancy
Apr	winter dormancy (winterkill exposure; snow cover is the protection) → jointing
May	heading / flowering
Jun	heading / flowering → harvest
Jul	post-harvest fallow
Aug	post-harvest fallow
Sep	post-harvest fallow
Oct	planting → emergence
Nov	winter dormancy
Dec	winter dormancy

USDelta / Mid-South measured

Winter wheat growth stage by month in United States — Delta / Mid-South. Cells marked critical are yield-determining.
Jan	winter dormancy
Feb	winter dormancy
Mar	winter dormancy
Apr	green-up → jointing
May	heading / flowering
Jun	heading / flowering → harvest
Jul	post-harvest fallow
Aug	post-harvest fallow
Sep	post-harvest fallow
Oct	post-harvest fallow → planting
Nov	emergence → winter dormancy
Dec	winter dormancy

USEastern Corn Belt measured

Winter wheat growth stage by month in United States — Eastern Corn Belt. Cells marked critical are yield-determining.
Jan	winter dormancy
Feb	winter dormancy
Mar	winter dormancy
Apr	winter dormancy (winterkill exposure; snow cover is the protection) → jointing
May	jointing → heading / flowering
Jun	heading / flowering
Jul	harvest → post-harvest fallow
Aug	post-harvest fallow
Sep	post-harvest fallow
Oct	post-harvest fallow → planting
Nov	emergence → winter dormancy
Dec	winter dormancy

USNorthern Plains measured

Winter wheat growth stage by month in United States — Northern Plains. Cells marked critical are yield-determining.
Jan	winter dormancy
Feb	winter dormancy
Mar	winter dormancy
Apr	winter dormancy
May	green-up → jointing
Jun	heading / flowering
Jul	heading / flowering → harvest
Aug	post-harvest fallow
Sep	post-harvest fallow → planting
Oct	emergence → winter dormancy
Nov	winter dormancy
Dec	winter dormancy

USSouthern High Plains measured

Winter wheat growth stage by month in United States — Southern High Plains. Cells marked critical are yield-determining.
Jan	winter dormancy
Feb	winter dormancy
Mar	winter dormancy
Apr	jointing → heading / flowering
May	heading / flowering
Jun	harvest → post-harvest fallow
Jul	post-harvest fallow
Aug	post-harvest fallow
Sep	post-harvest fallow
Oct	planting → emergence
Nov	winter dormancy
Dec	winter dormancy

USWestern Corn Belt measured

Winter wheat growth stage by month in United States — Western Corn Belt. Cells marked critical are yield-determining.
Jan	winter dormancy
Feb	winter dormancy
Mar	winter dormancy
Apr	winter dormancy
May	green-up → jointing
Jun	heading / flowering
Jul	heading / flowering → harvest
Aug	post-harvest fallow
Sep	post-harvest fallow → planting
Oct	emergence → winter dormancy
Nov	winter dormancy
Dec	winter dormancy

Cotton — 5 regions

BrazilMatopiba

Cotton growth stage by month in Brazil — Matopiba. Cells marked critical are yield-determining.
Jan	—not stated
Feb	—not stated
Mar	—not stated
Apr	—not stated
May	—not stated
Jun	harvest opens
Jul	harvest
Aug	harvest tail — dry season, no crop establishing
Sep	—not stated
Oct	—not stated
Nov	—not stated
Dec	—not stated

USCentral & Southern Plains (HRW) measured

Cotton growth stage by month in United States — Central & Southern Plains (HRW). Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground → planting
Jun	planting
Jul	squaring
Aug	flowering / boll set
Sep	flowering / boll set → bolls opening
Oct	bolls opening
Nov	harvest → post-harvest fallow
Dec	post-harvest fallow

USDelta / Mid-South measured

Cotton growth stage by month in United States — Delta / Mid-South. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting → emergence
Jun	vegetative
Jul	squaring (flower buds, pre-anthesis) → flowering / boll set
Aug	flowering / boll set
Sep	bolls opening
Oct	harvest → post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USSoutheast / Atlantic Coastal measured

Cotton growth stage by month in United States — Southeast / Atlantic Coastal. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground → planting
Jun	planting → squaring
Jul	squaring (flower buds, pre-anthesis) → flowering / boll set
Aug	flowering / boll set
Sep	bolls opening
Oct	bolls opening
Nov	post-harvest fallow
Dec	post-harvest fallow

USSouthern High Plains measured

Cotton growth stage by month in United States — Southern High Plains. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground → planting
Jun	planting
Jul	squaring
Aug	flowering / boll set
Sep	flowering / boll set → bolls opening
Oct	bolls opening
Nov	harvest → post-harvest fallow
Dec	post-harvest fallow

Sorghum — 5 regions

USCentral & Southern Plains (HRW) measured

Sorghum growth stage by month in United States — Central & Southern Plains (HRW). Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground
Jun	planting → emergence
Jul	vegetative
Aug	heading / flowering → coloring / grain fill
Sep	coloring / grain fill → maturity / dry-down
Oct	maturity / dry-down → harvest
Nov	post-harvest fallow
Dec	post-harvest fallow

USDelta / Mid-South measured

Sorghum growth stage by month in United States — Delta / Mid-South. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground → planting
May	planting
Jun	planting
Jul	heading / flowering
Aug	coloring / grain fill → maturity / dry-down
Sep	harvest → post-harvest fallow
Oct	post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USNorthern Plains measured

Sorghum growth stage by month in United States — Northern Plains. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground
Jun	planting
Jul	planting
Aug	heading / flowering → coloring / grain fill
Sep	coloring / grain fill → maturity / dry-down
Oct	harvest → post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USSouthern High Plains measured

Sorghum growth stage by month in United States — Southern High Plains. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting
Jun	planting
Jul	heading / flowering
Aug	coloring / grain fill → maturity / dry-down
Sep	maturity / dry-down → harvest
Oct	post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USWestern Corn Belt measured

Sorghum growth stage by month in United States — Western Corn Belt. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	no crop in ground → planting
Jun	planting
Jul	planting
Aug	heading / flowering → coloring / grain fill
Sep	coloring / grain fill → maturity / dry-down
Oct	maturity / dry-down → harvest
Nov	post-harvest fallow
Dec	post-harvest fallow

Durum wheat — 2 regions

USNorthern Plains measured

Durum wheat growth stage by month in United States — Northern Plains. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting → emergence
Jun	emergence → vegetative
Jul	heading / flowering → coloring / grain fill
Aug	maturity / dry-down → harvest
Sep	post-harvest fallow
Oct	post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USWestern Corn Belt measured

Durum wheat growth stage by month in United States — Western Corn Belt. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting → emergence
Jun	emergence → vegetative
Jul	heading / flowering → coloring / grain fill
Aug	maturity / dry-down → harvest
Sep	post-harvest fallow
Oct	post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

Spring wheat — 2 regions

USNorthern Plains measured

Spring wheat growth stage by month in United States — Northern Plains. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting → emergence
Jun	vegetative (canopy build) → jointing
Jul	heading / flowering → coloring / grain fill
Aug	maturity / dry-down → harvest
Sep	post-harvest fallow
Oct	post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

USWestern Corn Belt measured

Spring wheat growth stage by month in United States — Western Corn Belt. Cells marked critical are yield-determining.
Jan	no crop in ground
Feb	no crop in ground
Mar	no crop in ground
Apr	no crop in ground
May	planting → emergence
Jun	vegetative (canopy build) → jointing
Jul	heading / flowering → coloring / grain fill
Aug	maturity / dry-down → harvest
Sep	post-harvest fallow
Oct	post-harvest fallow
Nov	post-harvest fallow
Dec	post-harvest fallow

Wheat is split the way the data is: wheat covers the non-US regions, where the calendar is descriptive, while winter wheat, spring wheat and durum wheat are the US classes, each measured separately from NASS. They are different crops and are never pooled.

United States — measured, not asserted

Every region above the US block states a stage window from agronomic domain knowledge. The US is the exception: NASS has published weekly percent-of-crop-in-stage since 2000, we ingest it, and so the stage date is measured — the date each year the crop crosses 50% of acres in a stage, interpolated between the bracketing weekly reports, then taken as a median over 2005–present.

The spread is the deliverable, not the median. “Corn silks in July” cannot gate a weather read. 50% silking lands Jul 18 but has landed as early as Jul 9 and as late as Jul 26 — so a heat ridge in the first week of July and the same ridge in the third week hit two different crops, one still vegetative and one pollinating.

Crop	Stage	Median 50% date	Earliest	Latest	Spread	Years
spring wheat	planted	May 07	Apr 21	May 22	31d	22
corn	planted	May 07	Apr 25	May 20	25d	22
winter wheat	headed ◆	May 13	Apr 28	May 22	24d	22
soybeans	planted	May 19	May 10	Jun 06	27d	22
cotton	planted	May 20	May 12	May 26	14d	22
corn	emerged	May 20	May 12	Jun 04	23d	22
spring wheat	emerged	May 21	May 08	Jun 02	25d	22
sorghum	planted	May 31	May 21	Jun 09	19d	22
soybeans	emerged	May 31	May 24	Jun 14	21d	22
winter wheat	harvested	Jul 02	Jun 19	Jul 12	23d	22
spring wheat	headed ◆	Jul 03	Jun 23	Jul 15	22d	22
cotton	squaring	Jul 05	Jun 26	Jul 09	13d	22
soybeans	blooming ◆	Jul 15	Jul 09	Jul 25	16d	22
corn	silking ◆	Jul 18	Jul 09	Jul 26	17d	22
cotton	setting bolls ◆	Jul 28	Jul 21	Aug 03	13d	22
sorghum	headed ◆	Jul 30	Jul 26	Aug 06	11d	22
soybeans	setting pods ◆	Jul 31	Jul 25	Aug 09	15d	22
corn	dough ◆	Aug 08	Aug 02	Aug 20	18d	22
spring wheat	harvested	Aug 21	Aug 06	Sep 04	29d	22
sorghum	coloring ◆	Aug 27	Aug 21	Sep 01	11d	22
corn	dented ◆	Aug 27	Aug 16	Sep 06	21d	22
cotton	bolls opening	Sep 14	Sep 08	Sep 24	16d	21
corn	mature	Sep 18	Sep 07	Oct 02	25d	21
soybeans	dropping leaves	Sep 18	Sep 14	Sep 27	13d	21
sorghum	mature	Sep 21	Sep 18	Oct 01	13d	21
winter wheat	planted	Oct 04	Sep 29	Oct 12	13d	22
soybeans	harvested	Oct 11	Oct 05	Oct 31	26d	21
sorghum	harvested	Oct 16	Oct 09	Nov 04	26d	21
corn	harvested	Oct 18	Sep 29	Nov 13	45d	21
winter wheat	emerged	Oct 19	Oct 14	Oct 25	11d	22
cotton	harvested	Oct 31	Oct 22	Nov 11	20d	21

⚠ What is measured, and what is not. The table above covers corn, cotton, durum wheat, sorghum, soybeans, spring wheat, winter wheat (durum only in the Northern Plains and Western Corn Belt, where NASS publishes it) — wheat reported per class, so a winter wheat row and a spring wheat row are different crops and are never pooled. Cotton has no NASS bloom series: setting bolls is the first post-anthesis marker published, and it and bolls opening bracket the boll-fill window rather than either one naming it.

Region detail

Each card carries the region's own coverage note: which weather series it joins to, and where the stated timing is weaker than it looks.

Coffee

Brazil — arabicahigh confidence

brazil_arabica · coffee_weather.csv · coffee · S hemisphere

Critical months: Jan, Feb, Mar, Jun, Jul, Aug, Sep, Oct, Nov

Brazil — conilon / robusta (ES, RO, BA)review before copy

brazil_robusta · coffee_weather.csv · coffee · S hemisphere

Critical months: Jan, Feb, Mar, Aug, Sep, Oct, Nov

Central America — arabica (HN, GT, NI, CR)review before copy

central_america · coffee_weather.csv · coffee · N hemisphere

Critical months: Jan, Mar, Apr, Jun, Jul, Aug, Sep, Dec

Colombia — arabicareview before copy

colombia · coffee_weather.csv · coffee · N hemisphere

Critical months: Jan, Feb, Mar, Jul, Oct, Nov

Ethiopia — arabicareview before copy

ethiopia · coffee_weather.csv · coffee · N hemisphere

Critical months: Feb, Mar, Apr, Oct, Nov, Dec

Indonesia — robusta (Sumatra / Lampung)review before copy

indonesia_robusta · coffee_weather.csv · coffee · S hemisphere

Critical months: May, Jun, Jul, Sep, Oct, Nov

Vietnam — robusta (Central Highlands)high confidence

vietnam · coffee_weather.csv · coffee · N hemisphere

Critical months: Jan, Feb, Mar, Apr, Sep, Oct, Nov

Grains

China — North China Plain (winter wheat + summer corn)high confidence

china_ncp_wheat · no in-house dekad series · wheat, corn · N hemisphere

Critical months: Apr, May, Jun, Aug, Oct

No dekad series. Covered by seasonal EVENT models: china_ncp_dhw (dry-hot-wind, May-Jun) and china_harvest_rain (harvest-window rain, Jun). Both are silent outside their season by design — an empty month is not a data gap.

China — Northeast (corn & soybeans)high confidence

china_ne_corn_soy · no in-house dekad series · corn, soybeans · N hemisphere

Critical months: May, Jul, Aug, Sep

No dekad series. Covered by the seasonal china_ne_frost event model (early-autumn frost, Sep-Oct), silent outside its season by design.

Argentina — Pampashigh confidence

grain_argentina_pampas · grain_weather.csv · corn, soybeans, wheat · S hemisphere

Critical months: Jan, Feb, Oct, Nov, Dec

Australia — eastern wheat belthigh confidence

grain_australia_east · grain_weather.csv · wheat · S hemisphere

Critical months: Apr, May, Sep, Oct

Australia — Western Australia wheat belthigh confidence

grain_australia_west · grain_weather.csv · wheat · S hemisphere

Critical months: Apr, May, Sep, Oct

Brazil — Matopibahigh confidence

grain_brazil_matopiba · grain_weather.csv · soybeans, corn, cotton · S hemisphere

Critical months: Jan, Feb, Apr, May, Oct

France — wheathigh confidence

grain_france_wheat · grain_weather.csv · wheat · N hemisphere

Critical months: May, Jun, Oct

India — wheat (rabi)high confidence

grain_india_wheat · grain_weather.csv · wheat · N hemisphere

Critical months: Feb, Mar, Nov

Russia — wheathigh confidence

grain_russia_wheat · grain_weather.csv · wheat · N hemisphere

Critical months: Jan, Feb, May, Jun, Jul, Sep

Ukraine — wheathigh confidence

grain_ukraine_wheat · grain_weather.csv · wheat · N hemisphere

Critical months: Jan, Feb, May, Jun, Sep

United States — Central & Southern Plains (HRW)high confidence

us_central_south_plains · us_grain_weather.csv · cotton, sorghum, winter wheat · N hemisphere

Critical months: May, Jun, Aug, Sep

Stages are MEASURED from NASS Crop Progress 50% dates, not asserted — see kb/us-crop-phenology-observed.md. Regenerate with us_phenology_observed.py then update_us_phenology_calendar.py.

United States — Delta / Mid-Southreview before copy

us_delta_midsouth · us_grain_weather.csv · corn, cotton, sorghum, soybeans, winter wheat · N hemisphere

Critical months: May, Jun, Jul, Aug, Sep

AR/MS/LA/TN enter the panel only through COTTON and SORGHUM. Corn, soybean and wheat dates here still rest on Missouri alone, the northern edge of the Delta, and therefore run LATE for the region. Stages are MEASURED from NASS Crop Progress 50% dates, not asserted — see kb/us-crop-phenology-observed.md. Regenerate with us_phenology_observed.py then update_us_phenology_calendar.py.

United States — Eastern Corn Belthigh confidence

us_east_corn_belt · us_grain_weather.csv · corn, soybeans, winter wheat · N hemisphere

Critical months: May, Jun, Jul, Aug, Sep

Stages are MEASURED from NASS Crop Progress 50% dates, not asserted — see kb/us-crop-phenology-observed.md. Regenerate with us_phenology_observed.py then update_us_phenology_calendar.py.

United States — Northern Plainshigh confidence

us_northern_plains · us_grain_weather.csv · corn, durum wheat, sorghum, soybeans, spring wheat, winter wheat · N hemisphere

Critical months: Jun, Jul, Aug, Sep

Spring wheat and durum ARE now measured here (MT is in the panel), which is what this region grows. The winter wheat rows are a minor crop in the Dakotas and should not be read as the region's wheat. Stages are MEASURED from NASS Crop Progress 50% dates, not asserted — see kb/us-crop-phenology-observed.md. Regenerate with us_phenology_observed.py then update_us_phenology_calendar.py.

United States — Southeast / Atlantic Coastalreview before copy

us_southeast_atlantic · us_grain_weather.csv · cotton · N hemisphere

Critical months: Jul, Aug

GA/AL/SC/NC are in the panel for COTTON and (GA excepted) not for corn, soybeans or wheat. The region is cotton-timed; its other crops still fall back to the descriptive calendar. Stages are MEASURED from NASS Crop Progress 50% dates, not asserted — see kb/us-crop-phenology-observed.md. Regenerate with us_phenology_observed.py then update_us_phenology_calendar.py.

United States — Southern High Plainsreview before copy

us_southern_high_plains · us_grain_weather.csv · cotton, sorghum, winter wheat · N hemisphere

Critical months: Apr, May, Jul, Aug, Sep

TX and OK carry the whole region, and their statewide progress is dominated by areas outside the High Plains clip. Stages are MEASURED from NASS Crop Progress 50% dates, not asserted — see kb/us-crop-phenology-observed.md. Regenerate with us_phenology_observed.py then update_us_phenology_calendar.py.

United States — Western Corn Belthigh confidence

us_west_corn_belt · us_grain_weather.csv · corn, durum wheat, sorghum, soybeans, spring wheat, winter wheat · N hemisphere

Critical months: Jun, Jul, Aug, Sep

Stages are MEASURED from NASS Crop Progress 50% dates, not asserted — see kb/us-crop-phenology-observed.md. Regenerate with us_phenology_observed.py then update_us_phenology_calendar.py.

How good is this?

⚠ Outside the US these windows are agronomic domain knowledge, not derived from our data, and nothing in the pipeline validates them. Typical timing only. Real stages shift by weeks with the season, and shift systematically in ENSO years — which is the point of pairing this calendar with the index, not a defect in it.

Treat a stage boundary as ±1 dekad, not a hard date. Sowing and harvest both slide with the season.
Each window is a regional average over a bounding box, and several of those boxes span genuinely different growing conditions — Ethiopia, Central America and Australia East most of all.
This page does not forecast. It says which window a dekad falls in; it makes no claim about what will happen in it.
Timing is not impact. Whether an anomaly inside a window moves yield is a separate question with its own evidence, and it lives on Weather impacts by growth stage.
Cotton, cocoa and sugar have no windows at all, though we carry positioning and drought coverage on all three.

Generated 2026-09-06 from data/phenology_calendar.json and data/us_phenology_observed.json. The same content is available to machine clients through the SoftSignal MCP server as crop-phenology-calendar, us-crop-phenology-observed and weather-impacts-by-stage.