Was the forecast right for Chicago on Sat Sep 12?
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 Sat Sep 12 high anywhere from 66° to 77°; by the final call the field had settled to a median of 86°. The day verified at 88° against the MDW observations — cloudy.
GEM landed closest, off by 0.7°. AIFS ran 5° cold.
What every model said, at every lead
Daily-high calls for Sat Sep 12 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 · 2026-08-28 | — | 88° | — | — | 80° | — | — | 80–88° |
| 14d · 2026-08-29 | 76° | 85° | — | — | 78° | — | — | 76–85° |
| 13d · 2026-08-30 | 77° | 76° | 69° | — | 66° | — | — | 66–77° |
| 12d · 2026-08-31 | 73° | 70° | 65° | — | 84° | — | — | 65–84° |
| 11d · 2026-09-01 | 78° | 74° | 95° | — | 83° | — | — | 74–95° |
| 10d · 2026-09-02 | 89° | 92° | 86° | — | 84° | — | — | 84–92° |
| 9d · 2026-09-03 | 72° | 95° | 72° | — | 87° | — | — | 72–95° |
| 8d · 2026-09-04 | 83° | 68° | 86° | 81° | 77° | — | — | 68–86° |
| 7d · 2026-09-05 | 82° | 77° | 85° | 87° | 85° | — | — | 77–87° |
| 6d · 2026-09-06 | 81° | 83° | 77° | 81° | 90° | 80° | — | 77–90° |
| 5d · 2026-09-07 | 80° | 84° | 80° | 80° | 88° | 83° | 81° | 80–88° |
| 4d · 2026-09-08 | 81° | 83° | 91° | 82° | 83° | 78° | 83° | 78–91° |
| 3d · 2026-09-09 | 82° | 85° | 86° | 81° | 87° | 84° | 75° | 75–87° |
| 2d · 2026-09-10 | 82° | 84° | 82° | 82° | 88° | 83° | 80° | 80–88° |
| 1d · 2026-09-11 | 83° | 86° | 84° | 90° | 88° | 84° | 86° | 83–90° |
| 0d · 2026-09-12 | 83° | 87° | 86° | 89° | 87° | 85° | 86° | 83–89° |
| actual | 88° |
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.