Was the forecast right for Chicago on Sun Aug 2?
Chicago, Illinois · daily high temperature · forecasts from each model's archived runs, verified against ERA5
6 days out, 6 models put Chicago's Sun Aug 2 high anywhere from 75° to 80°; by the final call the field had settled to a median of 72°. ERA5 says the day verified at 72° with 0.02 in of precipitation — drizzle.
UKMO landed closest, off by 0.1°. ICON ran 5° hot.
What every model said, at every lead
Daily-high calls for Sun Aug 2 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 · 2026-07-27 | 77° | 80° | 79° | 75° | 78° | 79° | — | 75–80° |
| 5d · 2026-07-28 | 73° | 75° | 73° | 76° | 74° | 80° | 76° | 73–80° |
| 4d · 2026-07-29 | 73° | 72° | 74° | 76° | 71° | 73° | 71° | 71–76° |
| 3d · 2026-07-30 | 72° | 70° | 70° | 73° | 71° | 75° | 72° | 70–75° |
| 2d · 2026-07-31 | 73° | 71° | 70° | 74° | 71° | 76° | 69° | 69–76° |
| 1d · 2026-08-01 | 73° | 72° | 71° | 77° | 72° | 77° | 75° | 71–77° |
| 0d · 2026-08-02 | 73° | 72° | 70° | 75° | 71° | 77° | 72° | 70–77° |
| actual | 72° |
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.