Was the forecast right for Chicago on Sun Aug 16?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
13 days out, 4 models put Chicago's Sun Aug 16 high anywhere from 73° to 82°; by the final call the field had settled to a median of 86°. The ECMWF IFS analysis says the day verified at 88° with 0.35 in of precipitation — thunderstorms.
GEM landed closest, off by 1.2°. GFS ran 5° cold.
What every model said, at every lead
Daily-high calls for Sun Aug 16 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 · 2026-08-01 | — | 74° | — | — | 92° | — | — | 74–92° |
| 14d · 2026-08-02 | 82° | 80° | — | — | 78° | — | — | 78–82° |
| 13d · 2026-08-03 | 82° | 77° | 73° | — | 77° | — | — | 73–82° |
| 12d · 2026-08-04 | 74° | 68° | 77° | — | 77° | — | — | 68–77° |
| 11d · 2026-08-05 | 73° | 78° | 70° | — | 70° | — | — | 70–78° |
| 10d · 2026-08-06 | 70° | 72° | 80° | — | 70° | — | — | 70–80° |
| 9d · 2026-08-07 | 72° | 79° | 71° | — | 71° | — | — | 71–79° |
| 8d · 2026-08-08 | 76° | 74° | 73° | 80° | 77° | — | — | 73–80° |
| 7d · 2026-08-09 | 79° | 76° | 80° | 80° | 79° | — | — | 76–80° |
| 6d · 2026-08-10 | 79° | 83° | 77° | 83° | 78° | 78° | — | 77–83° |
| 5d · 2026-08-11 | 83° | 86° | 86° | 78° | 81° | 82° | 79° | 78–86° |
| 4d · 2026-08-12 | 79° | 81° | 86° | 77° | 80° | 84° | 85° | 77–86° |
| 3d · 2026-08-13 | 82° | 84° | 82° | 80° | 85° | 82° | 82° | 80–85° |
| 2d · 2026-08-14 | 82° | 83° | 83° | 81° | 85° | 84° | 88° | 81–88° |
| 1d · 2026-08-15 | 82° | 83° | 84° | 90° | 83° | 85° | 85° | 82–90° |
| 0d · 2026-08-16 | 83° | 86° | 84° | 89° | 83° | 86° | 89° | 83–89° |
| actual | 88° |
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 ECMWF IFS analysis (temperature_2m_max). Archive depth varies by city; receipts exist only for dates the archive watched arrive.