Was the forecast right for Chicago on Wed Aug 5?
Chicago, Illinois · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
10 days out, 4 models put Chicago's Wed Aug 5 high anywhere from 28° to 33°;by the final call, the day before, the field had settled to a median of 27°. The day verified at 29° against the ECMWF IFS analysis, with 10.2 mm of precipitation — rain.
UKMO landed closest, off by 0.1°. AIFS ran 5° cool.
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 |
|---|---|---|---|---|---|---|---|---|
| 10d · 2026-07-26 | 28° | 29° | 33° | — | 31° | — | — | 28–33° |
| 9d · 2026-07-27 | 29° | 26° | 32° | 24° | 32° | — | — | 24–32° |
| 8d · 2026-07-28 | 25° | 30° | 29° | 26° | 26° | — | — | 25–30° |
| 7d · 2026-07-29 | 26° | 28° | 29° | 29° | 28° | — | — | 26–29° |
| 6d · 2026-07-30 | 28° | 27° | 25° | 29° | 27° | 23° | 29° | 23–29° |
| 5d · 2026-07-31 | 27° | 26° | 27° | 28° | 29° | 26° | 27° | 26–29° |
| 4d · 2026-08-01 | 24° | 24° | 26° | 29° | 29° | 28° | 31° | 24–31° |
| 3d · 2026-08-02 | 24° | 26° | 28° | 25° | 28° | 24° | 30° | 24–30° |
| 2d · 2026-08-03 | 24° | 25° | 28° | 26° | 29° | 25° | 28° | 24–29° |
| 1d · 2026-08-04 | 24° | 26° | 30° | 31° | 27° | 27° | 29° | 24–31° |
| actual | 29° |
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.