Was the forecast right for Chicago on Fri Sep 4?
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 Fri Sep 4 high anywhere from 77° to 82°; by the final call the field had settled to a median of 93°. The day verified at 93° against the MDW observations — thunderstorms.
GEM landed closest, off by 0.2°. AIFS ran 9° cold.
What every model said, at every lead
Daily-high calls for Fri Sep 4 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 |
|---|---|---|---|---|---|---|---|---|
| 14d · 2026-08-21 | 70° | 82° | — | — | 98° | — | — | 70–98° |
| 13d · 2026-08-22 | 82° | 78° | 77° | — | 82° | — | — | 77–82° |
| 12d · 2026-08-23 | 76° | 73° | 67° | — | 79° | — | — | 67–79° |
| 11d · 2026-08-24 | 78° | 80° | 87° | — | 76° | — | — | 76–87° |
| 10d · 2026-08-25 | 82° | 96° | 76° | — | 84° | — | — | 76–96° |
| 9d · 2026-08-26 | 85° | 90° | 88° | — | 77° | — | — | 77–90° |
| 8d · 2026-08-27 | 87° | 89° | 79° | 94° | 97° | — | — | 79–97° |
| 7d · 2026-08-28 | 78° | 78° | 85° | 86° | 99° | — | — | 78–99° |
| 6d · 2026-08-29 | 78° | 81° | 93° | 78° | 94° | 95° | — | 78–95° |
| 5d · 2026-08-30 | 84° | 86° | 87° | 84° | 85° | 100° | 97° | 84–100° |
| 4d · 2026-08-31 | 86° | 82° | 88° | 77° | 96° | 90° | 81° | 77–96° |
| 3d · 2026-09-01 | 84° | 87° | 86° | 88° | 90° | 90° | 95° | 84–95° |
| 2d · 2026-09-02 | 84° | 84° | 88° | 93° | 95° | 95° | 97° | 84–97° |
| 1d · 2026-09-03 | 86° | 87° | 93° | 93° | 95° | 95° | 98° | 86–98° |
| 0d · 2026-09-04 | 84° | 92° | 91° | 93° | 96° | 94° | 98° | 84–98° |
| actual | 93° |
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.