The Spread

Was the forecast right for Chicago on Mon Aug 24?

Chicago, Illinois · daily high temperature in °C · forecasts from each model's archived runs, verified against the MDW observations

3 days out, 7 models put Chicago's Mon Aug 24 high anywhere from 23° to 28°; by the final call the field had settled to a median of 25°. The day verified at 26° against the MDW observations — partly cloudy.

GFS landed closest, off by 0.6°. AIFS ran 2° cold.

3 days out the models said 23–28; it hit 26. GFS led (off 0.6°C); AIFS ran 2°C cold.
The shareable card for this receipt — what this page looks like pasted into a thread.

What every model said, at every lead

Daily-high calls for Mon Aug 24 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 AIFSAIGFSECMWFGEMGFSICONUKMO Range
3d · 2026-08-21 23° 23° 23° 26° 28° 25° 26° 23–28°
2d · 2026-08-22 24° 24° 24° 25° 27° 24° 25° 24–27°
1d · 2026-08-23 24° 24° 26° 29° 26° 26° 26° 24–29°
0d · 2026-08-24 24° 24° 25° 28° 27° 26° 25° 24–28°
actual 26°

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.