Was the forecast right for Chicago on Mon Aug 10?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
14 days out, 4 models put Chicago's Mon Aug 10 high anywhere from 78° to 87°;by the final call, the day before, the field had settled to a median of 80°. The day verified at 84° against the ECMWF IFS analysis, with 0.74 in of precipitation — rain.
AIGFS landed closest, off by 1.9°. AIFS ran 6° cool.
What every model said, at every lead
Daily-high calls for Mon Aug 10 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 · 2026-07-26 | — | 83° | — | — | 84° | — | — | 83–84° |
| 14d · 2026-07-27 | 78° | 87° | 79° | — | 86° | — | — | 78–87° |
| 13d · 2026-07-28 | 82° | 78° | 86° | — | 82° | — | — | 78–86° |
| 12d · 2026-07-29 | 78° | 78° | 88° | — | 88° | — | — | 78–88° |
| 11d · 2026-07-30 | 82° | 66° | 83° | — | 72° | — | — | 66–83° |
| 10d · 2026-07-31 | 80° | 83° | 78° | — | 87° | — | — | 78–87° |
| 9d · 2026-08-01 | 74° | 78° | 78° | 86° | 78° | — | — | 74–86° |
| 8d · 2026-08-02 | 79° | 78° | 97° | 76° | 90° | — | — | 76–97° |
| 7d · 2026-08-03 | 78° | 75° | 92° | 81° | 83° | — | — | 75–92° |
| 6d · 2026-08-04 | 79° | 70° | 90° | 89° | 78° | 86° | 96° | 70–96° |
| 5d · 2026-08-05 | 83° | 73° | 88° | 90° | 79° | 90° | 96° | 73–96° |
| 4d · 2026-08-06 | 76° | 81° | 85° | 77° | 84° | 82° | 97° | 76–97° |
| 3d · 2026-08-07 | 76° | 76° | 85° | 79° | 90° | 84° | 89° | 76–90° |
| 2d · 2026-08-08 | 80° | 77° | 83° | 76° | 79° | 85° | 90° | 76–90° |
| 1d · 2026-08-09 | 78° | 82° | 81° | 80° | 79° | 87° | 79° | 78–87° |
| 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 the ECMWF IFS analysis (temperature_2m_max). The actual values are the ones in hand when this receipt was settled, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; receipts exist only for dates the archive watched arrive.