Was the forecast right for Chicago on Tue Sep 8?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the MDW observations
13 days out, 4 models put Chicago's Tue Sep 8 high anywhere from 70° to 90°; by the final call the field had settled to a median of 84°. The day verified at 87° against the MDW observations — cloudy.
GFS landed closest, off by 0.4°. AIFS ran 8° cold.
What every model said, at every lead
Daily-high calls for Tue Sep 8 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, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-24 | — | 82° | — | — | 80° | — | — | 80–82° |
| 14d · 2026-08-25 | 74° | 80° | — | — | 78° | — | — | 74–80° |
| 13d · 2026-08-26 | 80° | 70° | 90° | — | 81° | — | — | 70–90° |
| 12d · 2026-08-27 | 72° | 73° | 98° | — | 90° | — | — | 72–98° |
| 11d · 2026-08-28 | 78° | 72° | 86° | — | 81° | — | — | 72–86° |
| 10d · 2026-08-29 | 81° | 96° | 102° | — | 97° | — | — | 81–102° |
| 9d · 2026-08-30 | 80° | 76° | 82° | — | 82° | — | — | 76–82° |
| 8d · 2026-08-31 | 80° | 83° | 82° | 85° | 84° | — | — | 80–85° |
| 7d · 2026-09-01 | 82° | 82° | 84° | 86° | 71° | — | — | 71–86° |
| 6d · 2026-09-02 | 83° | 91° | 87° | 87° | 93° | 87° | — | 83–93° |
| 5d · 2026-09-03 | 78° | 88° | 86° | 85° | 85° | 91° | 89° | 78–91° |
| 4d · 2026-09-04 | 82° | 85° | 90° | 83° | 89° | 88° | 88° | 82–90° |
| 3d · 2026-09-05 | 82° | 84° | 85° | 84° | 87° | 84° | 90° | 82–90° |
| 2d · 2026-09-06 | 81° | 84° | 84° | 82° | 87° | 84° | 88° | 81–88° |
| 1d · 2026-09-07 | 80° | 83° | 84° | 92° | 88° | 84° | 87° | 80–92° |
| 0d · 2026-09-08 | 79° | 83° | 84° | 90° | 87° | 84° | 84° | 79–90° |
| actual | 87° |
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. Archive depth varies by city; receipts exist only for dates the archive watched arrive.