Was the forecast right for Chicago on Thu Sep 10?
Chicago, Illinois · daily high temperature in °C · forecasts from each model's archived runs, verified against the MDW observations
14 days out, 4 models put Chicago's Thu Sep 10 high anywhere from 25° to 36°;by the final call, the day before, the field had settled to a median of 25°. The day verified at 24° against the MDW observations — cloudy.
ECMWF landed closest, off by 0.1°. GFS ran 3° warm.
What every model said, at every lead
Daily-high calls for Thu Sep 10 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 Chicago scoreboard shows them, labeled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-26 | — | 27° | — | — | 30° | — | — | 27–30° |
| 14d · 2026-08-27 | 33° | 29° | 25° | — | 36° | — | — | 25–36° |
| 13d · 2026-08-28 | 31° | 25° | 36° | — | 32° | — | — | 25–36° |
| 12d · 2026-08-29 | 32° | 31° | 28° | — | 22° | — | — | 22–32° |
| 11d · 2026-08-30 | 30° | 34° | 22° | — | 29° | — | — | 22–34° |
| 10d · 2026-08-31 | 31° | 33° | 27° | — | 30° | — | — | 27–33° |
| 9d · 2026-09-01 | 28° | 20° | 27° | 34° | 24° | — | — | 20–34° |
| 8d · 2026-09-02 | 27° | 24° | 23° | 29° | 28° | — | — | 23–29° |
| 7d · 2026-09-03 | 24° | 27° | 25° | 32° | 29° | — | — | 24–32° |
| 6d · 2026-09-04 | 25° | 24° | 27° | 24° | 26° | 25° | 27° | 24–27° |
| 5d · 2026-09-05 | 23° | 25° | 28° | 25° | 30° | 25° | 24° | 23–30° |
| 4d · 2026-09-06 | 24° | 24° | 25° | 23° | 25° | 24° | 25° | 23–25° |
| 3d · 2026-09-07 | 24° | 24° | 26° | 24° | 25° | 26° | 27° | 24–27° |
| 2d · 2026-09-08 | 24° | 23° | 25° | 25° | 26° | 25° | 25° | 23–26° |
| 1d · 2026-09-09 | 24° | 24° | 25° | 27° | 27° | 26° | 25° | 24–27° |
| actual | 24° |
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 Chicago — 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 MDW observations. The actual values are the ones in hand when this day was verified, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; verified days exist only for dates the archive watched arrive.