Was the forecast right for Chicago on Fri Jul 31?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
5 days out, 7 models put Chicago's Fri Jul 31 high anywhere from 76° to 88°;by the final call, the day before, the field had settled to a median of 82°. The day verified at 81° against the ECMWF IFS analysis, with 0.49 in of precipitation — rain.
GFS landed closest, off by 0.5°. UKMO ran 3° warm.
What every model said, at every lead
Daily-high calls for Fri Jul 31 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 |
|---|---|---|---|---|---|---|---|---|
| 5d · 2026-07-26 | 80° | 81° | 78° | 78° | 76° | 88° | 87° | 76–88° |
| 4d · 2026-07-27 | 79° | 81° | 87° | 80° | 77° | 87° | 88° | 77–88° |
| 3d · 2026-07-28 | 77° | 78° | 81° | 72° | 80° | 83° | 83° | 72–83° |
| 2d · 2026-07-29 | 77° | 78° | 85° | 82° | 81° | 83° | 81° | 77–85° |
| 1d · 2026-07-30 | 79° | 80° | 82° | 84° | 81° | 83° | 84° | 79–84° |
| actual | 81° |
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). 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.