Was the forecast right for Chicago on Sun Aug 9?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
14 days out, 4 models put Chicago's Sun Aug 9 high anywhere from 80° to 94°;by the final call, the day before, the field had settled to a median of 83°. The day verified at 78° against the ECMWF IFS analysis, with 0.76 in of precipitation — rain.
ICON landed closest, off by 1.9°. GEM ran 13° warm.
What every model said, at every lead
Daily-high calls for Sun Aug 9 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 |
|---|---|---|---|---|---|---|---|---|
| 14d · 2026-07-26 | 80° | 80° | 94° | — | 84° | — | — | 80–94° |
| 13d · 2026-07-27 | 86° | 86° | 82° | — | 75° | — | — | 75–86° |
| 12d · 2026-07-28 | 79° | 78° | 83° | — | 94° | — | — | 78–94° |
| 11d · 2026-07-29 | 78° | 78° | 83° | — | 86° | — | — | 78–86° |
| 10d · 2026-07-30 | 81° | 80° | 94° | — | 84° | — | — | 80–94° |
| 9d · 2026-07-31 | 84° | 79° | 79° | 86° | 88° | — | — | 79–88° |
| 8d · 2026-08-01 | 80° | 79° | 89° | 74° | 82° | — | — | 74–89° |
| 7d · 2026-08-02 | 84° | 80° | 90° | 82° | 94° | — | — | 80–94° |
| 6d · 2026-08-03 | 82° | 83° | 89° | 86° | 88° | 89° | 93° | 82–93° |
| 5d · 2026-08-04 | 85° | 83° | 86° | 83° | 87° | 84° | 93° | 83–93° |
| 4d · 2026-08-05 | 80° | 83° | 83° | 80° | 85° | 86° | 83° | 80–86° |
| 3d · 2026-08-06 | 79° | 79° | 83° | 81° | 88° | 85° | 86° | 79–88° |
| 2d · 2026-08-07 | 77° | 78° | 86° | 80° | 88° | 78° | 91° | 77–91° |
| 1d · 2026-08-08 | 80° | 84° | 83° | 91° | 88° | 80° | 80° | 80–91° |
| actual | 78° |
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.