Was the forecast right for Chicago on Sat Aug 1?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
6 days out, 7 models put Chicago's Sat Aug 1 high anywhere from 73° to 88°;by the final call, the day before, the field had settled to a median of 71°. The day verified at 72° against the ECMWF IFS analysis, with 3.06 in of precipitation — rain.
ECMWF landed closest, off by 0.1°. AIGFS ran 3° cool.
What every model said, at every lead
Daily-high calls for Sat Aug 1 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 · 2026-07-26 | 75° | 75° | 77° | 73° | 78° | 88° | 76° | 73–88° |
| 5d · 2026-07-27 | 75° | 76° | 77° | 75° | 80° | 82° | 79° | 75–82° |
| 4d · 2026-07-28 | 72° | 70° | 72° | 70° | 72° | 72° | 73° | 70–73° |
| 3d · 2026-07-29 | 75° | 68° | 74° | 72° | 68° | 73° | 71° | 68–75° |
| 2d · 2026-07-30 | 71° | 70° | 72° | 73° | 69° | 72° | 71° | 69–73° |
| 1d · 2026-07-31 | 71° | 69° | 72° | 71° | 70° | 72° | 74° | 69–74° |
| actual | 72° |
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.