Was the forecast right for St. Louis on Sun Sep 6?
St. Louis, Missouri · daily high temperature in °C · forecasts from each model's archived runs, verified against the STL observations
12 days out, 4 models put St. Louis's Sun Sep 6 high anywhere from 26° to 34°;by the final call, the day before, the field had settled to a median of 32°. The day verified at 32° against the STL observations — cloudy.
ECMWF landed closest, off by 0.2°. GEM ran 4° warm.
What every model said, at every lead
Daily-high calls for Sun Sep 6 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 |
|---|---|---|---|---|---|---|---|---|
| 12d · 2026-08-25 | 26° | 27° | 26° | — | 34° | — | — | 26–34° |
| 11d · 2026-08-26 | 25° | 39° | 35° | — | 31° | — | — | 25–39° |
| 10d · 2026-08-27 | 35° | 23° | 35° | — | 42° | — | — | 23–42° |
| 9d · 2026-08-28 | 27° | 31° | 35° | 38° | 37° | — | — | 27–38° |
| 8d · 2026-08-29 | 32° | 26° | 38° | 32° | 39° | — | — | 26–39° |
| 7d · 2026-08-30 | 30° | 35° | 34° | 31° | 39° | — | — | 30–39° |
| 6d · 2026-08-31 | 30° | 33° | 34° | 34° | 34° | 34° | 35° | 30–35° |
| 5d · 2026-09-01 | 31° | 33° | 34° | 35° | 36° | 33° | 36° | 31–36° |
| 4d · 2026-09-02 | 32° | 35° | 34° | 32° | 37° | 34° | 36° | 32–37° |
| 3d · 2026-09-03 | 30° | 33° | 34° | 34° | 35° | 33° | 33° | 30–35° |
| 2d · 2026-09-04 | 30° | 33° | 32° | 33° | 34° | 32° | 33° | 30–34° |
| 1d · 2026-09-05 | 30° | 33° | 32° | 36° | 34° | 32° | 32° | 30–36° |
| actual | 32° |
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. The actual values are the ones in hand when this receipt was settled, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; receipts exist only for dates the archive watched arrive.