Was the forecast right for Chicago on Fri Sep 4?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the MDW observations
14 days out, 4 models put Chicago's Fri Sep 4 high anywhere from 69° to 76°;by the final call, the day before, the field had settled to a median of 93°. The day verified at 93° against the MDW observations — thunderstorms.
GEM landed closest, off by 0.4°. AIFS ran 5° cool.
What every model said, at every lead
Daily-high calls for Fri Sep 4 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 |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-20 | — | 94° | — | — | 82° | — | — | 82–94° |
| 14d · 2026-08-21 | 74° | 73° | 69° | — | 76° | — | — | 69–76° |
| 13d · 2026-08-22 | 78° | 77° | 78° | — | 78° | — | — | 77–78° |
| 12d · 2026-08-23 | 89° | 78° | 74° | — | 79° | — | — | 74–89° |
| 11d · 2026-08-24 | 77° | 81° | 78° | — | 91° | — | — | 77–91° |
| 10d · 2026-08-25 | 88° | 85° | 87° | — | 95° | — | — | 85–95° |
| 9d · 2026-08-26 | 88° | 90° | 84° | 92° | 90° | — | — | 84–92° |
| 8d · 2026-08-27 | 78° | 89° | 77° | 92° | 101° | — | — | 77–101° |
| 7d · 2026-08-28 | 77° | 79° | 85° | 79° | 90° | — | — | 77–90° |
| 6d · 2026-08-29 | 83° | 76° | 96° | 80° | 92° | 97° | 96° | 76–97° |
| 5d · 2026-08-30 | 82° | 85° | 89° | 78° | 95° | 98° | 96° | 78–98° |
| 4d · 2026-08-31 | 82° | 85° | 86° | 84° | 96° | 94° | 91° | 82–96° |
| 3d · 2026-09-01 | 82° | 84° | 88° | 90° | 96° | 93° | 94° | 82–96° |
| 2d · 2026-09-02 | 87° | 88° | 89° | 92° | 97° | 97° | 96° | 87–97° |
| 1d · 2026-09-03 | 88° | 90° | 90° | 93° | 96° | 94° | 97° | 88–97° |
| actual | 93° |
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.