Was the forecast right for Chicago on Wed Sep 9?
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 Wed Sep 9 high anywhere from 68° to 92°; by the final call the field had settled to a median of 80°. The day verified at 80° against the MDW observations, with 0.04 in of precipitation — showers.
GEM landed closest, off by 0.5°. AIGFS ran 6° cold.
What every model said, at every lead
Daily-high calls for Wed Sep 9 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 · 2026-08-25 | — | 80° | — | — | 82° | — | — | 80–82° |
| 14d · 2026-08-26 | 76° | 73° | — | — | 76° | — | — | 73–76° |
| 13d · 2026-08-27 | 68° | 74° | 92° | — | 85° | — | — | 68–92° |
| 12d · 2026-08-28 | 85° | 82° | 81° | — | 78° | — | — | 78–85° |
| 11d · 2026-08-29 | 87° | 93° | 88° | — | 80° | — | — | 80–93° |
| 10d · 2026-08-30 | 86° | 82° | 82° | — | 82° | — | — | 82–86° |
| 9d · 2026-08-31 | 78° | 87° | 78° | — | 80° | — | — | 78–87° |
| 8d · 2026-09-01 | 88° | 75° | 91° | 94° | 86° | — | — | 75–94° |
| 7d · 2026-09-02 | 88° | 93° | 91° | 93° | 90° | — | — | 88–93° |
| 6d · 2026-09-03 | 84° | 91° | 87° | 88° | 91° | 79° | — | 79–91° |
| 5d · 2026-09-04 | 84° | 85° | 92° | 86° | 88° | 87° | 92° | 84–92° |
| 4d · 2026-09-05 | 82° | 84° | 88° | 84° | 89° | 86° | 87° | 82–89° |
| 3d · 2026-09-06 | 79° | 74° | 82° | 80° | 78° | 79° | 80° | 74–82° |
| 2d · 2026-09-07 | 78° | 76° | 83° | 78° | 84° | 78° | 81° | 76–84° |
| 1d · 2026-09-08 | 77° | 77° | 83° | 80° | 76° | 77° | 80° | 76–83° |
| 0d · 2026-09-09 | 78° | 74° | 82° | 80° | 77° | 83° | 86° | 74–86° |
| actual | 80° |
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.