Was the forecast right for Chicago on Fri Sep 11?
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 11 high anywhere from 76° to 90°; by the final call the field had settled to a median of 79°. The day verified at 81° against the MDW observations — cloudy.
ICON landed closest, off by 0.9°. AIFS ran 4° cold.
What every model said, at every lead
Daily-high calls for Fri Sep 11 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 · 2026-08-27 | — | 88° | — | — | 76° | — | — | 76–88° |
| 14d · 2026-08-28 | 82° | 87° | — | — | 79° | — | — | 79–87° |
| 13d · 2026-08-29 | 76° | 83° | 90° | — | 81° | — | — | 76–90° |
| 12d · 2026-08-30 | 75° | 85° | 61° | — | 63° | — | — | 61–85° |
| 11d · 2026-08-31 | 82° | 89° | 73° | — | 90° | — | — | 73–90° |
| 10d · 2026-09-01 | 89° | 96° | 98° | — | 72° | — | — | 72–98° |
| 9d · 2026-09-02 | 76° | 91° | 84° | — | 82° | — | — | 76–91° |
| 8d · 2026-09-03 | 69° | 94° | 69° | 93° | 80° | — | — | 69–94° |
| 7d · 2026-09-04 | 77° | 81° | 73° | 69° | 70° | — | — | 69–81° |
| 6d · 2026-09-05 | 81° | 80° | 83° | 82° | 77° | 81° | — | 77–83° |
| 5d · 2026-09-06 | 76° | 79° | 78° | 74° | 82° | 76° | 81° | 74–82° |
| 4d · 2026-09-07 | 77° | 79° | 79° | 77° | 85° | 77° | 78° | 77–85° |
| 3d · 2026-09-08 | 77° | 76° | 81° | 78° | 81° | 79° | 79° | 76–81° |
| 2d · 2026-09-09 | 77° | 78° | 79° | 74° | 83° | 78° | 80° | 74–83° |
| 1d · 2026-09-10 | 78° | 77° | 77° | 84° | 83° | 81° | 80° | 77–84° |
| 0d · 2026-09-11 | 77° | 79° | 79° | 83° | 83° | 80° | 79° | 77–83° |
| actual | 81° |
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.