Was the forecast right for Chicago on Sun Sep 6?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the MDW observations
14 days out, 4 models put Chicago's Sun Sep 6 high anywhere from 76° to 82°;by the final call, the day before, the field had settled to a median of 77°. The day verified at 79° against the MDW observations — cloudy.
GFS landed closest, off by 1.1°. ECMWF ran 4° cool.
What every model said, at every lead
Daily-high calls for Sun Sep 6 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 · 2026-08-22 | — | 71° | — | — | 80° | — | — | 71–80° |
| 14d · 2026-08-23 | 81° | 82° | 79° | — | 76° | — | — | 76–82° |
| 13d · 2026-08-24 | 89° | 93° | 78° | — | 91° | — | — | 78–93° |
| 12d · 2026-08-25 | 79° | 76° | 73° | — | 80° | — | — | 73–80° |
| 11d · 2026-08-26 | 78° | 93° | 87° | — | 80° | — | — | 78–93° |
| 10d · 2026-08-27 | 86° | 74° | 87° | — | 94° | — | — | 74–94° |
| 9d · 2026-08-28 | 75° | 78° | 84° | 94° | 84° | — | — | 75–94° |
| 8d · 2026-08-29 | 81° | 73° | 87° | 85° | 92° | — | — | 73–92° |
| 7d · 2026-08-30 | 78° | 88° | 81° | 83° | 86° | — | — | 78–88° |
| 6d · 2026-08-31 | 79° | 82° | 86° | 79° | 80° | 81° | 84° | 79–86° |
| 5d · 2026-09-01 | 79° | 83° | 82° | 80° | 86° | 82° | 96° | 79–96° |
| 4d · 2026-09-02 | 79° | 82° | 77° | 76° | 82° | 81° | 83° | 76–83° |
| 3d · 2026-09-03 | 75° | 76° | 78° | 79° | 80° | 77° | 77° | 75–80° |
| 2d · 2026-09-04 | 76° | 77° | 74° | 78° | 80° | 78° | 79° | 74–80° |
| 1d · 2026-09-05 | 76° | 75° | 74° | 82° | 80° | 78° | 77° | 74–82° |
| actual | 79° |
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. The actual values are the ones in hand when this receipt was settled, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; receipts exist only for dates the archive watched arrive.