Feature guide · USDA + weather + seasonality

Understand every part of
Corn Crop & Weather.

See how far the crop has developed, how its condition is changing and what recent weather looks like. This guide explains the dashboard’s numbers, comparisons and limits, one feature at a time.

Updated September 24, 2026Product guide · Stock SeasonalityIllustrative examples, not live readings
Open corn futures (ZC=F) in the dashboard, then select Crop & Weather. The leaf button opens the view. Each i button gives a quick explanation and a link to the relevant section here.
01 · Development

Crop Progress: how far has the crop developed?

Each row shows the reported percentage reaching a particular stage. The stages overlap: a harvested crop has also passed earlier stages. Do not add the rows together.

Crop ProgressEXAMPLE
USDA weekly progress vs. 5-year average
StageCurrent5Y avgVs. normal
Planted97%96%+1 pp
Emerged97%97%0 pp
Silking97%97%0 pp
Dough92%89%+3 pp
Dented92%91%+1 pp
Mature58%55%+3 pp
Harvested13%11%+2 pp
Harvested progress
13% +2 pp ahead
Current 13%
5Y Avg 11%
Dashboard illustration · not live dataRead across the highlighted Harvested row: 13% current, 11% average, +2 percentage points.
StageWhat it describes
PlantedPlanting completed.
EmergedPlants have appeared above the soil.
SilkingSilks are emerging from ears.
DoughKernels have reached the dough-like development stage.
DentedKernels have developed the characteristic dent.
MatureThe crop has reached maturity.
HarvestedThe crop has been gathered from the field.

USDA’s definitions describe the reporting stages in more detail.

Current, 5Y Avg and “vs. normal”

Current is the latest reported share for that stage. 5Y Avg is the report’s five-year average for the comparable week. The badge subtracts the average from the current reading and reports percentage points (pp).

Illustrative example

13% harvested − 11% five-year average = +2 pp. It means harvesting is ahead in percentage terms. It does not establish that harvest is two days early or that prices will rise.

Current phase and the progress panel

The highlighted phase is an app selection based on the latest available progress readings. It identifies the most advanced listed stage with progress above 0% and below 98%, with a fallback when no stage meets that rule. “Harvested” as the phase therefore does not mean the entire crop has been harvested.

The lower panel compares the selected stage with its five-year average. A weekly trend is shown when enough observations are stored. A single reading supports a comparison, but not a meaningful trend line.

02 · Crop health

Crop Condition: how is the crop rated?

USDA reports five condition categories: Very Poor, Poor, Fair, Good and Excellent. The donut combines Good and Excellent. The colored breakdown shows the share in each category.

Crop ConditionEXAMPLE
USDA weekly crop condition
57%Good / Excellent
Condition Index3.47 / 5+0.00 vs. last week
Condition Breakdown (This Week)
Very Poor6%Poor11%Fair26%Good44%Excellent13%
Good / Excellent comparison
Last week57%0 pp this week
Last year66%Current is 9 pp lower
Good/Excellent is 57% — unchanged from last week and 9 pp below last year.
Dashboard illustration · not live dataThe donut, category breakdown and comparison panel describe the same crop condition reading.
Good / Excellent

If Good is 44% and Excellent is 13%, the donut reads 57%. This is a condition rating, not the probability of a profitable trade or a yield forecast.

The condition index: a weighted score from 1 to 5

Stock Seasonality summarizes the five percentages with weights of 1 through 5. This displayed index is an app calculation from the USDA categories.

Index = (1 × Very Poor + 2 × Poor + 3 × Fair + 4 × Good + 5 × Excellent) ÷ 100

For 6%, 11%, 26%, 44% and 13%, the index is 3.47 / 5. Higher readings give more weight to the better-rated categories; the score is not a forecast of future production.

Weekly and yearly comparisons

The comparison block puts the current Good/Excellent reading beside the supplied previous-week and previous-year values. For example, 57% versus 57% last week is unchanged; 57% versus 66% last year is 9 pp lower. The index’s weekly change is in index points, not percentage points.

03 · Recent conditions

Weather Risk: what do the four tiles measure?

The weather tiles use NASA POWER modeled estimates at ten fixed points, one in each selected state. They summarize the latest seven complete days shared by all ten points. Their baseline is the 2001–2020 monthly climatology; it is not a weather forecast.

Weather RiskEXAMPLE
Recent conditions · 10-state sample
☂ Precipitation Anomaly+178.1%Wetter than baseline
♨ Temperature Anomaly+4.1°FWarmer than baseline
◆ Root-zone Wetness−2.6%Below baseline wetness
! Drought Area · D1+34.8%State land area in D1–D4
These tiles describe recent conditions. They are not a weather forecast.
Dashboard illustration · not live dataEach tile has its own unit and baseline. Compare like with like.
TileCalculation and interpretation
Precipitation anomalyAt each point: (seven-day rain total ÷ expected total − 1) × 100. Positive means wetter than the baseline; negative means drier.
Temperature anomalySeven-day mean temperature minus the mean baseline, expressed in °F. A positive reading means warmer; it is a temperature difference, not the actual temperature.
Root-zone wetnessPercentage difference between the modeled root-zone wetness index and its baseline. It is not a field measurement of soil water content or of the top one meter.
Drought Area · D1+The equal-weight mean of ten state land-area percentages in moderate drought or worse: D1 through D4. It does not measure the share of corn acreage exposed.

For rain, temperature and wetness, the regional number is the simple average of the ten point anomalies. Each day in a seven-day window uses the climatology for its month, including windows crossing month boundaries. The samples are not weighted by crop acreage.

How to read the small lines

The three NASA lines show daily endpoints of rolling seven-day anomalies. The drought line shows weekly reports, and its change is measured in percentage points versus the prior available report. A rising line describes a changing metric; it is not automatically an increase in trading risk.

Illustrative example

A rainfall anomaly of +50% means the sampled total was 1.5 times its baseline. A temperature anomaly of +4°F means four degrees warmer than the baseline. These two values measure different things.

04 · Regional detail

The Corn Belt map: select a state

The map covers Iowa, Illinois, Indiana, Ohio, Nebraska, Kansas, Minnesota, South Dakota, Wisconsin and Missouri. Select a marker to view the sample’s location, rain anomaly, temperature anomaly and wetness anomaly, plus the state’s D1+ drought area share.

Corn Belt Weather OverviewEXAMPLE
7-day rainfall anomaly · illustrative marker colors
IowaIAIllinoisILIndianaINOhioOHNebraskaNEKansasKSMinnesotaMNSouth DakotaSDWisconsinWIMissouriMO
🟠 Drier● Near normal🟢 Wetter
Iowa · sample 42°, −93.5°Rain +305.9% · Temp +1.3°F · Wetness +36.2% · D1+ area 6.8%
In the dashboard, select a state marker to see this detail panel.
Dashboard illustration · not live dataExample of the map and selected-state panel. Use the live dashboard to select markers.

Marker colors describe rainfall at the sampled location: orange below −10%, pale green within ±10%, and green above +10%. Neutral markers indicate unavailable weather samples. The boundaries provide geography; a point’s color does not establish uniform conditions across the whole state.

“Near normal” is the app’s ±10% display band. It is not an official drought classification.

05 · Historical context

Seasonality Impact: compare context with history

The chart uses the seasonal path from the current market analysis. It shows the average normalized historical calendar-year pattern for the selected history, with a base index of 100. Read January through December across the horizontal axis.

Seasonality ImpactEXAMPLE
Calendar Seasonality · base index 100 · schematic curve
10510095JanAprJulOctDec
Current context: Harvested · progress ahead of the five-year average. The seasonal curve does not include weather adjustments.
Current Outlook
Current phaseHarvested
Crop timing+2 pp vs 5Y
Crop condition57% G/E
Weather premiumNot modeled
RegimeNot assessed
Dashboard illustration · not live dataSchematic chart for orientation only; it is not a historical series or a forecast.

The vertical axis is a seasonal index, not a futures price in dollars. It adjusts to the data range so changes remain visible. The dotted 100 line is the reference level. An index of 105 is 5% above that normalized base; it does not promise a 5% return from today.

Current context and Current Outlook

Current phase, crop timing and crop condition summarize the USDA readings. “Weather premium: Not modeled” and “Regime: Not assessed” mean those estimates have not been calculated. The grey “Crop-Adjusted · next” legend is not a second active data series.

The current seasonal curve is not weather-adjusted. Connecting weather data does not by itself produce a validated price model. The LIVE badge describes the connected dashboard, not an intraday market feed.

Use the panel to compare historical tendencies with current reported conditions. It does not establish that weather caused a price move or provide a standalone trade recommendation.

06 · The report in one glance

This Week’s USDA Snapshot

The lower strip brings together the selected stage’s progress, Good/Excellent condition and the condition index. The progress badge compares with the five-year average; the condition badge compares with last week. The report date and full-report link help you check the source.

This Week’s USDA SnapshotEXAMPLE
Key takeaways from the Crop Progress & Condition report
Harvested progress13%vs. 11% five-year average · +2 pp
Good / Excellent57%Unchanged from last week
Condition Index3.47 / 5Weighted crop condition
Report at a glance
Harvested 13% vs 11% five-year average; Good/Excellent 57%. Summary calculated from example readings.
Dashboard illustration · not live dataThe summary strip brings the progress and condition readings together.

The “Report at a glance” text is a rule-based summary calculated from the displayed USDA readings. It is not a quotation from USDA, an analyst forecast, or a weather-adjusted recommendation.

07 · Freshness

When does the dashboard update?

DataHow the app checks it
USDA crop reportsA daily scheduled job checks for available reports. Crop Progress is a weekly publication during the reporting season; daily checks do not mean a new report exists every day.
NASA weatherThe server refreshes at startup and on a weather request when its six-hour cache has expired. Upstream data can lag the current date.
DroughtPulled during the weather refresh, using the latest common weekly report across all ten states.
Seasonal curveComes from the selected market analysis and history range, separately from the USDA and weather feeds.

The displayed dates refer to the observations or report, not the time you opened the page. Reopen or refresh the page to fetch the latest crop snapshot; leaving the tab open does not continuously reload USDA data.

Missing, delayed or stale readings

A missing observation is not zero. Regional weather needs all ten samples and a complete seven-day window. Drought needs a report date shared by all ten states. If a refresh fails, the app may retain the last successful section and mark it stale. Weather older than seven days and drought older than fourteen days are also marked stale. A stale reading remains historical context; check its date before interpreting it as current.

Sources and further reading

The calculations above describe the Stock Seasonality implementation. These primary sources explain the underlying datasets.

Related: Corn seasonality research using the CORN ETF. That research page uses a different instrument from the ZC=F futures view explained here.

Put the numbers in context.

Open corn, choose Crop & Weather, and use the information buttons whenever you need an explanation.

Open corn dashboard →