Was the forecast right for Chicago on Tue Sep 1?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the MDW observations
11 days out, 4 models put Chicago's Tue Sep 1 high anywhere from 76° to 98°; by the final call the field had settled to a median of 94°. The day verified at 94° against the MDW observations — drizzle.
GFS landed closest, off by 0.1°. AIFS ran 5° cold.
What every model said, at every lead
Daily-high calls for Tue Sep 1 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 |
|---|---|---|---|---|---|---|---|---|
| 11d · 2026-08-21 | 76° | 80° | 80° | — | 98° | — | — | 76–98° |
| 10d · 2026-08-22 | 80° | 83° | 71° | — | 74° | — | — | 71–83° |
| 9d · 2026-08-23 | 81° | 82° | 78° | — | 94° | — | — | 78–94° |
| 8d · 2026-08-24 | 84° | 93° | 92° | 80° | 86° | — | — | 80–93° |
| 7d · 2026-08-25 | 83° | 83° | 80° | 92° | 80° | — | — | 80–92° |
| 6d · 2026-08-26 | 84° | 94° | 92° | 90° | 94° | 88° | — | 84–94° |
| 5d · 2026-08-27 | 86° | 90° | 86° | 93° | 94° | 91° | 91° | 86–94° |
| 4d · 2026-08-28 | 88° | 93° | 95° | 87° | 96° | 94° | 93° | 87–96° |
| 3d · 2026-08-29 | 88° | 91° | 95° | 90° | 95° | 95° | 92° | 88–95° |
| 2d · 2026-08-30 | 90° | 91° | 91° | 91° | 94° | 93° | 87° | 87–94° |
| 1d · 2026-08-31 | 90° | 90° | 87° | 99° | 91° | 94° | 95° | 87–99° |
| 0d · 2026-09-01 | 89° | 94° | 91° | 98° | 94° | 92° | 96° | 89–98° |
| actual | 94° |
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.