Was the forecast right for Chicago on Mon Sep 7?
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 Mon Sep 7 high anywhere from 72° to 91°; by the final call the field had settled to a median of 78°. The day verified at 80° against the MDW observations — cloudy.
ICON landed closest, off by 1.4°. GFS ran 4° hot.
What every model said, at every lead
Daily-high calls for Mon Sep 7 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 · 2026-08-23 | — | 70° | — | — | 87° | — | — | 70–87° |
| 14d · 2026-08-24 | 75° | 75° | — | — | 88° | — | — | 75–88° |
| 13d · 2026-08-25 | 78° | 76° | 72° | — | 91° | — | — | 72–91° |
| 12d · 2026-08-26 | 76° | 77° | 87° | — | 85° | — | — | 76–87° |
| 11d · 2026-08-27 | 79° | 89° | 89° | — | 89° | — | — | 79–89° |
| 10d · 2026-08-28 | 80° | 87° | 92° | — | 80° | — | — | 80–92° |
| 9d · 2026-08-29 | 78° | 83° | 95° | — | 99° | — | — | 78–99° |
| 8d · 2026-08-30 | 78° | 76° | 75° | 80° | 79° | — | — | 75–80° |
| 7d · 2026-08-31 | 77° | 78° | 74° | 82° | 85° | — | — | 74–85° |
| 6d · 2026-09-01 | 81° | 85° | 82° | 82° | 90° | 83° | — | 81–90° |
| 5d · 2026-09-02 | 80° | 83° | 79° | 82° | 87° | 83° | 84° | 79–87° |
| 4d · 2026-09-03 | 78° | 81° | 79° | 77° | 79° | 82° | 79° | 77–82° |
| 3d · 2026-09-04 | 79° | 79° | 81° | 77° | 81° | 80° | 79° | 77–81° |
| 2d · 2026-09-05 | 78° | 79° | 76° | 77° | 81° | 77° | 79° | 76–81° |
| 1d · 2026-09-06 | 77° | 78° | 76° | 84° | 82° | 78° | 78° | 76–84° |
| 0d · 2026-09-07 | 77° | 78° | 78° | 82° | 84° | 79° | 78° | 77–84° |
| 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.