Was the forecast right for St. Louis on Mon Aug 31?
St. Louis, Missouri · daily high temperature in °F · forecasts from each model's archived runs, verified against the STL observations
6 days out, 6 models put St. Louis's Mon Aug 31 high anywhere from 81° to 102°; by the final call the field had settled to a median of 99°. The day verified at 99° against the STL observations — cloudy.
ECMWF landed closest, off by 0.1°. GEM ran 3° hot.
What every model said, at every lead
Daily-high calls for Mon Aug 31 as each model's runs approached it — the last archived run per day. NBM and The Spread's own blend are consensus products and stay out of these ranges and rankings; the St. Louis scoreboard shows them, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 6d · 2026-08-25 | 93° | 92° | 98° | 92° | 102° | 81° | — | 81–102° |
| 5d · 2026-08-26 | 96° | 96° | 99° | 95° | 102° | 98° | 93° | 93–102° |
| 4d · 2026-08-27 | 96° | 94° | 101° | 94° | 103° | 96° | 92° | 92–103° |
| 3d · 2026-08-28 | 96° | 94° | 100° | 95° | 106° | 97° | 94° | 94–106° |
| 2d · 2026-08-29 | 96° | 95° | 101° | 96° | 106° | 97° | 96° | 95–106° |
| 1d · 2026-08-30 | 96° | 96° | 99° | 101° | 101° | 98° | 97° | 96–101° |
| 0d · 2026-08-31 | 97° | 99° | 99° | 102° | 101° | 99° | 97° | 97–102° |
| actual | 99° |
Read it honestly
This is one date, not a league table. A model can win a day it deserved to lose; rankings only mean something over a window. For that, see which model has been most accurate in St. Louis — or every city The Spread scores.
Forecasts are what each model's archived runs said at the time, captured at The Spread's sweep times — never reconstructed after the fact. Truth is the STL observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.