Home  ›  Signals  ›  Z1227 Iowa Minimum Temperature Frost Risk

· Analytic

Z1227 Iowa Minimum Temperature Frost Risk

Daily minimum temperature for Iowa from OpenMeteo state-aggregate data, z-scored on 5-year rolling window and polarity-inverted so cold days register as positive signal values. A simple frost-risk indicator , low Iowa Tmin during late-spring planting or early-fall harvest windows signals yield-stress regimes.

Current reading

-0.199

NORMAL

DORMANT · WAITING FOR APR

DAILY · SIGNAL

As of Oct 30, 2026. Updated nightly. · NEXT WINDOW APRIL 2027

Current composite

-0.2173

On the plus-or-minus one scale; Iowa Tmin modestly warm vs 5y norm

SEASONAL STATE

DORMANT · WAITING FOR APR

The planting-season frost-risk window has closed. The signal is in off-season drift mode until April. Current readings reflect October-March temperature cycles rather than live frost-risk firing.

Signal state

Normal

1 day in episode

All-time percentile

47.3th

Near median of 36 years Historical sample is dominated by in-season (April-May) firings; off-season readings carry seasonal-temperature-cycle information rather than active frost-risk.

Historical sample is dominated by in-season (April-May) firings; off-season readings carry seasonal-temperature-cycle information rather than active frost-risk.

extreme-pos corn fwd 60d

+1.45%

2,737 days (30.5%), HAC t +2.49 sig at 5% Historical sample is dominated by in-season (April-May) firings; off-season readings carry seasonal-temperature-cycle information rather than active frost-risk.

Historical sample is dominated by in-season (April-May) firings; off-season readings carry seasonal-temperature-cycle information rather than active frost-risk.

extreme-neg corn fwd 60d

-1.94%

3,291 days (36.7%), HAC t -2.68 sig at 1% Historical sample is dominated by in-season (April-May) firings; off-season readings carry seasonal-temperature-cycle information rather than active frost-risk.

Historical sample is dominated by in-season (April-May) firings; off-season readings carry seasonal-temperature-cycle information rather than active frost-risk.

LOCKED portfolio weight

7.7%

1/13 equal-weight in Layer 1 base sleeve, polarity +1

OBJECTIVE

Iowa produces approximately 19 percent of US corn , the single largest state share , and Iowa’s late-spring and early-fall frost events can material impact yield outcomes. May frost damages young corn seedlings; September frost truncates grain fill before the crop fully matures. This signal queries OpenMeteo daily minimum temperature state-aggregate data for Iowa, computes an average per day, z-scores on a 5-year (1,260-day) rolling window, and polarity-inverts so negative Tmin (cold) maps to positive signal values. The empirical pattern across 36 years is cleanly directional. extreme-pos state (val above plus 0.5, Iowa Tmin significantly below 5-year rolling norm) delivers mean corn fwd 60d of plus 1.45 percent (HAC Newey-West t plus 2.49, significant at 5 percent, 2,737 state-days). extreme-neg state (val below minus 0.5, Iowa Tmin significantly above norm) delivers minus 1.94 percent (HAC t minus 2.68, significant at 1 percent, 3,291 state-days). Both tails directionally consistent with cold-is-bullish-corn thesis via frost-stress mechanism. The signal reads -0.199 as of October 23 2026 in moderate-neg territory for 2 consecutive trading day at the 47.3 percentile. Current conditions reflect Iowa Tmin running modestly above the 5-year rolling norm. The signal contributes 7.7 percent weight to the LOCKED corn portfolio v1_1 Layer 1 base sleeve with polarity sign plus one.

LIVE CHART

THE TAKEAWAY

THE REGIME MAP

Behavior across the Iowa daily minimum temperature z-score (OpenMeteo state-aggregate, 5-year rolling z, polarity-inverted so cold reads positive). The planting-season frost-risk mechanism fires strongest during the April-May window; off-season readings reflect seasonal temperature cycles. CBOT corn benchmark.

The historical pattern

THE TRACK RECORD

Scroll inside the table for the full history. Forward 60-day SPY is measured from each run’s start date; a reader cannot trade off a start-date they only identify in hindsight, so this is a transparency log, not an alpha claim. Asterisked (*) returns are partial. The run is less than 60 trading days old. The full 60-day comparable fills in as more data arrives.

The engine queries `weather_data.OPENMETEO_IOWA_CORN_BELT_TMIN_DAILY` for daily Iowa minimum temperature. Averages per date. Forward-fills daily. Z-scores on 1,260-day rolling window with 252-day minimum. Polarity-inverts (`sig = -z`). Clips to plus-or-minus 3. Tanh-bounds. Five-state machine on the final the primary composite.

Not investment advice · The analysis on this page is informational and educational. Signal readings, historical case figures, and empirical statistics are derived from publicly available data and are provided without warranty. Hypothetical performance results have inherent limitations, including the benefit of hindsight. Readers who intend to trade should consult a licensed investment professional and see the research brief for the full disclaimer.

Last refreshed Nov 02, 2026 01:11 PM ET