Was the forecast right for Chicago on Thu Aug 27?
Chicago, Illinois · daily high temperature in °C · forecasts from each model's archived runs, verified against the MDW observations
6 days out, 6 models put Chicago's Thu Aug 27 high anywhere from 25° to 31°; by the final call the field had settled to a median of 27°. The day verified at 27° against the MDW observations — drizzle.
ECMWF landed closest, off by 0.2°. GFS ran 2° hot.
What every model said, at every lead
Daily-high calls for Thu Aug 27 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 · 2026-08-21 | 25° | 28° | 28° | 25° | 31° | 31° | — | 25–31° |
| 5d · 2026-08-22 | 25° | 26° | 28° | 26° | 26° | 26° | 24° | 24–28° |
| 4d · 2026-08-23 | 26° | 27° | 28° | 24° | 30° | 26° | 26° | 24–30° |
| 3d · 2026-08-24 | 25° | 27° | 28° | 26° | 30° | 27° | 26° | 25–30° |
| 2d · 2026-08-25 | 26° | 26° | 27° | 26° | 30° | 28° | 26° | 26–30° |
| 1d · 2026-08-26 | 27° | 27° | 27° | 27° | 29° | 27° | 26° | 26–29° |
| 0d · 2026-08-27 | 26° | 26° | 27° | 28° | 29° | 27° | 26° | 26–29° |
| actual | 27° |
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 MDW observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.