Was the forecast right for Chicago on Tue Sep 15?
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 Tue Sep 15 high anywhere from 75° to 96°; by the final call the field had settled to a median of 85°. The day verified at 85° against the MDW observations, with 0.02 in of precipitation — thunderstorms.
ICON landed closest, off by 0.2°. AIGFS ran 6° cold.
What every model said, at every lead
Daily-high calls for Tue Sep 15 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 · 2026-08-31 | — | 64° | — | — | 74° | — | — | 64–74° |
| 14d · 2026-09-01 | 79° | 89° | — | — | 70° | — | — | 70–89° |
| 13d · 2026-09-02 | 75° | 77° | 94° | — | 96° | — | — | 75–96° |
| 12d · 2026-09-03 | 77° | 71° | 87° | — | 73° | — | — | 71–87° |
| 11d · 2026-09-04 | 84° | 81° | 75° | — | 74° | — | — | 74–84° |
| 10d · 2026-09-05 | 80° | 88° | 78° | — | 80° | — | — | 78–88° |
| 9d · 2026-09-06 | 84° | 91° | 74° | — | 66° | — | — | 66–91° |
| 8d · 2026-09-07 | 76° | 79° | 82° | 66° | 66° | — | — | 66–82° |
| 7d · 2026-09-08 | 74° | 82° | 77° | 64° | 77° | — | — | 64–82° |
| 6d · 2026-09-09 | 85° | 89° | 84° | 85° | 76° | 81° | — | 76–89° |
| 5d · 2026-09-10 | 78° | 85° | 90° | 88° | 84° | 91° | 86° | 78–91° |
| 4d · 2026-09-11 | 79° | 89° | 93° | 86° | 86° | 90° | 93° | 79–93° |
| 3d · 2026-09-12 | 80° | 82° | 94° | 85° | 87° | 83° | 86° | 80–94° |
| 2d · 2026-09-13 | 79° | 77° | 90° | 83° | 79° | 81° | 83° | 77–90° |
| 1d · 2026-09-14 | 80° | 79° | 86° | 84° | 81° | 84° | 82° | 79–86° |
| 0d · 2026-09-15 | 79° | 79° | 88° | 88° | 84° | 85° | 86° | 79–88° |
| actual | 85° |
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.