Was the forecast right for Chicago on Fri Aug 28?

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

8 days out, 5 models put Chicago's Fri Aug 28 high anywhere from 20° to 27°;by the final call, the day before, the field had settled to a median of 28°. The day verified at 29° against the MDW observations — drizzle.

GFS landed closest, off by 0.2°. AIFS ran 2° cool.

8 days out the models said 20–27; it hit 29. GFS led (off 0.2°C); AIFS ran 2°C cool. — 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 Fri Aug 28 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
8d · 2026-08-20	20°	26°	23°	23°	27°	—	—	20–27°
7d · 2026-08-21	21°	26°	25°	24°	30°	—	—	21–30°
6d · 2026-08-22	26°	24°	24°	26°	28°	28°	26°	24–28°
5d · 2026-08-23	24°	26°	29°	25°	26°	28°	27°	24–29°
4d · 2026-08-24	26°	25°	27°	25°	30°	28°	22°	22–30°
3d · 2026-08-25	26°	27°	27°	26°	30°	27°	26°	26–30°
2d · 2026-08-26	27°	27°	29°	27°	30°	28°	27°	27–30°
1d · 2026-08-27	27°	27°	27°	30°	29°	28°	28°	27–30°
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 MDW observations. 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.