Was the forecast right for Chicago on Wed Aug 5?
Chicago, Illinois · daily high temperature · forecasts from each model's archived runs, verified against ERA5
9 days out, 4 models put Chicago's Wed Aug 5 high anywhere from 78° to 84°; by the final call the field had settled to a median of 81°. ERA5 says the day verified at 84° with 0.4 in of precipitation — rain.
UKMO landed closest, off by 1.3°. AIFS ran 6° cold.
What every model said, at every lead
Daily-high calls for Wed Aug 5 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 |
|---|---|---|---|---|---|---|---|---|
| 9d · 2026-07-27 | 84° | 81° | 82° | — | 78° | — | — | 78–84° |
| 8d · 2026-07-28 | 80° | 84° | 87° | 77° | 85° | — | — | 77–87° |
| 7d · 2026-07-29 | 74° | 83° | 86° | 84° | 86° | — | — | 74–86° |
| 6d · 2026-07-30 | 81° | 82° | 83° | 83° | 85° | 76° | — | 76–85° |
| 5d · 2026-07-31 | 79° | 82° | 80° | 83° | 82° | 82° | 85° | 79–85° |
| 4d · 2026-08-01 | 76° | 79° | 81° | 83° | 83° | 82° | 86° | 76–86° |
| 3d · 2026-08-02 | 77° | 78° | 83° | 78° | 85° | 75° | 89° | 75–89° |
| 2d · 2026-08-03 | 75° | 77° | 83° | 76° | 83° | 74° | 82° | 74–83° |
| 1d · 2026-08-04 | 76° | 76° | 84° | 83° | 78° | 80° | 82° | 76–84° |
| 0d · 2026-08-05 | 77° | 80° | 82° | 86° | 81° | 81° | 85° | 77–86° |
| actual | 84° |
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 ERA5 reanalysis (temperature_2m_max). Archive depth varies by city; receipts exist only for dates the archive watched arrive.