Was the forecast right for Chicago on Thu Aug 27?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the MDW observations
6 days out, 6 models put Chicago's Thu Aug 27 high anywhere from 76° to 88°; by the final call the field had settled to a median of 80°. The day verified at 81° against the MDW observations — drizzle.
ECMWF landed closest, off by 0.3°. GFS ran 4° hot.
What every model said, at every lead
Daily-high calls for Thu Aug 27 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 |
|---|---|---|---|---|---|---|---|---|
| 6d · 2026-08-21 | 76° | 82° | 83° | 77° | 88° | 87° | — | 76–88° |
| 5d · 2026-08-22 | 77° | 79° | 83° | 80° | 78° | 80° | 76° | 76–83° |
| 4d · 2026-08-23 | 79° | 80° | 82° | 75° | 86° | 78° | 80° | 75–86° |
| 3d · 2026-08-24 | 77° | 80° | 82° | 79° | 85° | 81° | 80° | 77–85° |
| 2d · 2026-08-25 | 79° | 80° | 81° | 79° | 85° | 82° | 78° | 78–85° |
| 1d · 2026-08-26 | 80° | 81° | 81° | 80° | 85° | 81° | 79° | 79–85° |
| 0d · 2026-08-27 | 79° | 80° | 81° | 82° | 85° | 80° | 80° | 79–85° |
| 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. Archive depth varies by city; receipts exist only for dates the archive watched arrive.