Was the forecast right for Chicago on Thu Jul 30?
Chicago, Illinois · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
3 days out, 7 models put Chicago's Thu Jul 30 high anywhere from 27° to 32°; by the final call the field had settled to a median of 29°. The day verified at 29° against the ECMWF IFS analysis — cloudy.
AIGFS landed closest, off by 0.1°. GFS ran 4° cold.
What every model said, at every lead
Daily-high calls for Thu Jul 30 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 |
|---|---|---|---|---|---|---|---|---|
| 3d · 2026-07-27 | 28° | 30° | 30° | 27° | 32° | 31° | 31° | 27–32° |
| 2d · 2026-07-28 | 27° | 29° | 30° | 27° | 30° | 30° | 30° | 27–30° |
| 1d · 2026-07-29 | 28° | 28° | 31° | 28° | 25° | 31° | 30° | 25–31° |
| 0d · 2026-07-30 | 29° | 29° | 30° | 28° | 25° | 31° | 30° | 25–31° |
| 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). Archive depth varies by city; receipts exist only for dates the archive watched arrive.