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
14 days out, 4 models put Chicago's Fri Sep 11 high anywhere from 75° to 85°;by the final call, the day before, the field had settled to a median of 79°. The day verified at 81° against the MDW observations — cloudy.
ICON landed closest, off by 0.4°. AIFS ran 4° cool.
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, labeled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-27 | — | 90° | — | — | 86° | — | — | 86–90° |
| 14d · 2026-08-28 | 78° | 76° | 85° | — | 75° | — | — | 75–85° |
| 13d · 2026-08-29 | 77° | 91° | 83° | — | 68° | — | — | 68–91° |
| 12d · 2026-08-30 | 89° | 79° | 78° | — | 69° | — | — | 69–89° |
| 11d · 2026-08-31 | 85° | 92° | 94° | — | 78° | — | — | 78–94° |
| 10d · 2026-09-01 | 73° | 73° | 79° | — | 74° | — | — | 73–79° |
| 9d · 2026-09-02 | 76° | 92° | 69° | 80° | 96° | — | — | 69–96° |
| 8d · 2026-09-03 | 66° | 84° | 73° | 83° | 73° | — | — | 66–84° |
| 7d · 2026-09-04 | 80° | 80° | 85° | 76° | 82° | — | — | 76–85° |
| 6d · 2026-09-05 | 76° | 82° | 83° | 78° | 90° | 75° | 78° | 75–90° |
| 5d · 2026-09-06 | 77° | 78° | 79° | 75° | 80° | 79° | 78° | 75–80° |
| 4d · 2026-09-07 | 77° | 78° | 78° | 74° | 83° | 78° | 79° | 74–83° |
| 3d · 2026-09-08 | 76° | 77° | 79° | 75° | 84° | 79° | 80° | 75–84° |
| 2d · 2026-09-09 | 78° | 77° | 77° | 78° | 83° | 80° | 78° | 77–83° |
| 1d · 2026-09-10 | 77° | 78° | 78° | 83° | 84° | 81° | 79° | 77–84° |
| 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. The actual values are the ones in hand when this day was verified, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; verified days exist only for dates the archive watched arrive.