Was the forecast right for Chicago on Mon Aug 24?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the MDW observations
3 days out, 7 models put Chicago's Mon Aug 24 high anywhere from 74° to 82°; by the final call the field had settled to a median of 77°. The day verified at 79° against the MDW observations — partly cloudy.
GFS landed closest, off by 1.1°. AIFS ran 4° cold.
What every model said, at every lead
Daily-high calls for Mon Aug 24 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 |
|---|---|---|---|---|---|---|---|---|
| 3d · 2026-08-21 | 74° | 74° | 74° | 78° | 82° | 78° | 78° | 74–82° |
| 2d · 2026-08-22 | 75° | 75° | 76° | 77° | 80° | 75° | 77° | 75–80° |
| 1d · 2026-08-23 | 75° | 75° | 79° | 84° | 80° | 78° | 78° | 75–84° |
| 0d · 2026-08-24 | 75° | 76° | 77° | 82° | 80° | 78° | 77° | 75–82° |
| 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. Archive depth varies by city; receipts exist only for dates the archive watched arrive.