KSTL / Wed Oct 21 / OFFICIAL STATION RECORD

St. Louis, MOHigh ≥ 77°F

CONSENSUS FORECAST21%Oct 19 · 14:28 UTC

THE FORECAST FIELD

Who takes which side?

0% · NO50%YES · 100%

38%

28%

20%

16%

Consensus

21%

Probabilities derived from each source’s mean and spread. Forecasts may have different initialization times.

HOW A MODEL CONTRACT WORKS

Head-to-head preview

ILLUSTRATIVE · NOT EXECUTED

AIFSYES 23.6¢Risks 23.60u

ICONNO 76.4¢Risks 76.40u

100 contracts at the midpoint of these model probabilities. Each contract pays 1u to the winning side.

AIFS +76.40u · ICON −76.40u

These are current forecast comparisons, not locked entries. No credits have been committed. Read the proposed policy →

FOLLOW THE RUNS

Probability history

Recorded Reconstructed

Reconstructed from archived summary forecasts using a shared lead-dependent Gaussian error model. Times are initializations, not verified release times.

AIFS SingleICONGFSUKMETGEMIFS archive

Inspect a forecast 2026-10-20T06:00:00+00:00 · UTC

View the forecast data

UTC	AIFS	ICON	GFS	UKMET	GEM	IFS*
2026-10-06T12:00:00+00:00	0.0%	—	—	—	—	0.3%
2026-10-06T18:00:00+00:00	51.6%	—	—	—	—	—
2026-10-07T00:00:00+00:00	0.3%	—	—	—	—	12.6%
2026-10-07T06:00:00+00:00	1.4%	—	—	—	—	—
2026-10-07T12:00:00+00:00	9.1%	—	—	—	—	12.3%
2026-10-07T18:00:00+00:00	0.2%	—	—	—	—	—
2026-10-08T00:00:00+00:00	0.6%	—	—	—	—	6.9%
2026-10-08T06:00:00+00:00	27.4%	—	—	—	—	—
2026-10-08T12:00:00+00:00	16.9%	—	—	—	—	18.2%
2026-10-08T18:00:00+00:00	13.1%	—	—	—	—	—
2026-10-09T00:00:00+00:00	15.2%	—	—	—	—	18.2%
2026-10-09T06:00:00+00:00	11.0%	—	—	—	—	—
2026-10-09T12:00:00+00:00	17.9%	—	—	—	—	24.0%
2026-10-09T18:00:00+00:00	46.3%	—	—	—	—	—
2026-10-10T00:00:00+00:00	46.8%	—	—	—	—	28.8%
2026-10-10T06:00:00+00:00	33.0%	—	—	—	—	—
2026-10-10T12:00:00+00:00	46.3%	—	—	—	—	33.4%
2026-10-10T18:00:00+00:00	32.2%	—	—	—	—	—
2026-10-11T00:00:00+00:00	46.7%	—	—	—	—	33.0%
2026-10-11T06:00:00+00:00	56.1%	—	25.1%	—	—	—
2026-10-11T12:00:00+00:00	12.7%	—	—	—	—	33.5%
2026-10-11T18:00:00+00:00	18.5%	—	—	—	—	—
2026-10-12T00:00:00+00:00	10.8%	—	1.8%	—	—	39.6%
2026-10-12T06:00:00+00:00	7.6%	—	68.9%	—	—	—
2026-10-12T12:00:00+00:00	22.4%	—	—	—	—	33.0%
2026-10-12T18:00:00+00:00	11.7%	—	—	—	—	—
2026-10-13T00:00:00+00:00	7.4%	—	—	—	—	38.2%
2026-10-13T06:00:00+00:00	24.0%	—	12.4%	—	—	—
2026-10-13T12:00:00+00:00	12.3%	—	10.1%	—	—	31.2%
2026-10-13T18:00:00+00:00	54.6%	—	50.7%	—	—	—
2026-10-14T00:00:00+00:00	59.4%	2.7%	14.7%	—	—	26.0%
2026-10-14T06:00:00+00:00	53.4%	—	82.5%	—	—	—
2026-10-14T12:00:00+00:00	30.5%	21.4%	54.2%	0.4%	—	11.5%
2026-10-14T18:00:00+00:00	35.3%	—	57.8%	—	—	—
2026-10-15T00:00:00+00:00	37.8%	22.1%	44.9%	3.3%	—	16.1%
2026-10-15T06:00:00+00:00	46.3%	—	46.3%	—	—	—
2026-10-15T12:00:00+00:00	34.4%	28.9%	39.4%	9.7%	—	16.9%
2026-10-15T18:00:00+00:00	30.6%	—	40.7%	—	—	—
2026-10-16T00:00:00+00:00	34.5%	22.4%	32.3%	13.6%	—	9.7%
2026-10-16T06:00:00+00:00	30.4%	—	23.1%	—	—	—
2026-10-16T12:00:00+00:00	25.1%	15.7%	35.3%	11.6%	—	14.3%
2026-10-16T18:00:00+00:00	28.8%	2.5%	33.4%	—	—	0.0%
2026-10-17T00:00:00+00:00	23.4%	2.8%	36.3%	8.3%	—	9.0%
2026-10-17T06:00:00+00:00	19.6%	6.3%	42.0%	—	—	8.1%
2026-10-17T12:00:00+00:00	17.8%	3.6%	36.4%	3.8%	—	6.1%
2026-10-17T18:00:00+00:00	18.4%	1.7%	33.5%	—	—	5.3%
2026-10-18T00:00:00+00:00	19.0%	5.4%	37.6%	2.9%	—	5.9%
2026-10-18T06:00:00+00:00	14.0%	4.4%	43.0%	—	—	3.5%
2026-10-18T12:00:00+00:00	15.7%	3.8%	39.8%	0.8%	—	3.5%
2026-10-18T18:00:00+00:00	17.6%	3.8%	42.6%	—	—	—
2026-10-19T00:00:00+00:00	19.0%	10.9%	46.7%	2.0%	—	6.2%
2026-10-19T06:00:00+00:00	9.7%	5.7%	48.9%	0.0%	—	2.4%
2026-10-19T12:00:00+00:00	12.1%	5.7%	41.9%	0.3%	0.0%	2.9%
2026-10-19T18:00:00+00:00	17.5%	13.2%	48.8%	0.7%	—	3.7%
2026-10-20T00:00:00+00:00	19.1%	8.0%	50.0%	1.3%	14.4%	6.3%
2026-10-20T06:00:00+00:00	8.2%	—	46.1%	1.6%	—	2.1%

THE MODEL BOX SCORE

Forecasts & evidence

MODEL	YES	MEAN	SPREAD σ	INITIALIZATION UTC	BRIER ↓
NWS forecast	56%	77.0°F	3.4°F	2026-10-19 03:00	Pending
AIFS Single	38%	75.3°F	4.0°F	2026-10-19 06:00	Pending
WeatherNext 2	28%	74.7°F	3.1°F	2026-10-19 00:00	Pending
National Blend	24%	75.0°F	2.2°F	2026-10-19 06:00	Pending
IFS HRES	20%	73.1°F	4.1°F	2026-10-19 00:00	Pending
IFS Ensemble	16%	72.7°F	3.7°F	2026-10-19 00:00	Pending
ICON	9%	71.7°F	3.6°F	2026-10-19 00:00	Pending

Spread is the standard deviation used in the probability approximation. It is not a measured confidence rating. Brier here scores the latest recorded snapshot, not a league deadline.

SETTLEMENT & PROVENANCE

High ≥ 77°F · KSTL

Daily temperature props settle on the ACIS official station record. Inclusive and strict thresholds retain their exact meanings. Provisional observations do not replace the settlement record.

WP-KSTL-20261021-TMAX-GE77
Opened Oct 17 · 04:41 UTC

Original listing: St. Louis high ≥ 77°F · Wed Oct 21

Original prop, full history & receipt ↗