Was the forecast right for Chicago on Sat Aug 29?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the MDW observations
9 days out, 4 models put Chicago's Sat Aug 29 high anywhere from 70° to 83°;by the final call, the day before, the field had settled to a median of 81°. The day verified at 82° against the MDW observations — drizzle.
ICON landed closest, off by 0.1°. AIFS ran 3° cool.
What every model said, at every lead
Daily-high calls for Sat Aug 29 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 |
|---|---|---|---|---|---|---|---|---|
| 9d · 2026-08-20 | 70° | 81° | 72° | — | 83° | — | — | 70–83° |
| 8d · 2026-08-21 | 73° | 84° | 78° | 77° | 87° | — | — | 73–87° |
| 7d · 2026-08-22 | 79° | 78° | 83° | 79° | 74° | — | — | 74–83° |
| 6d · 2026-08-23 | 80° | 82° | 84° | 76° | 74° | 84° | 82° | 74–84° |
| 5d · 2026-08-24 | 77° | 83° | 83° | 82° | 82° | 83° | 74° | 74–83° |
| 4d · 2026-08-25 | 81° | 84° | 82° | 81° | 85° | 81° | 81° | 81–85° |
| 3d · 2026-08-26 | 80° | 82° | 84° | 79° | 80° | 80° | 82° | 79–84° |
| 2d · 2026-08-27 | 78° | 82° | 83° | 82° | 77° | 81° | 85° | 77–85° |
| 1d · 2026-08-28 | 79° | 81° | 81° | 85° | 79° | 82° | 85° | 79–85° |
| actual | 82° |
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.