Was the forecast right for Chicago on Sat Aug 15?
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 Sat Aug 15 high anywhere from 77° to 82°;by the final call, the day before, the field had settled to a median of 79°. The day verified at 84° against the ECMWF IFS analysis, with 0.64 in of precipitation — thunderstorms.
UKMO landed closest, off by 0.3°. AIGFS ran 9° cool.
What every model said, at every lead
Daily-high calls for Sat Aug 15 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 · 2026-07-31 | — | 73° | — | — | 83° | — | — | 73–83° |
| 14d · 2026-08-01 | 81° | 80° | 82° | — | 77° | — | — | 77–82° |
| 13d · 2026-08-02 | 83° | 80° | 79° | — | 71° | — | — | 71–83° |
| 12d · 2026-08-03 | 75° | 68° | 74° | — | 85° | — | — | 68–85° |
| 11d · 2026-08-04 | 76° | 69° | 73° | — | 72° | — | — | 69–76° |
| 10d · 2026-08-05 | 77° | 74° | 72° | — | 75° | — | — | 72–77° |
| 9d · 2026-08-06 | 70° | 70° | 75° | 70° | 78° | — | — | 70–78° |
| 8d · 2026-08-07 | 75° | 72° | 78° | 74° | 83° | — | — | 72–83° |
| 7d · 2026-08-08 | 75° | 70° | 82° | 74° | 75° | — | — | 70–82° |
| 6d · 2026-08-09 | 75° | 70° | 84° | 73° | 84° | 89° | 92° | 70–92° |
| 5d · 2026-08-10 | 74° | 76° | 82° | 78° | 82° | 92° | 95° | 74–95° |
| 4d · 2026-08-11 | 80° | 80° | 81° | 78° | 89° | 88° | 74° | 74–89° |
| 3d · 2026-08-12 | 78° | 79° | 82° | 76° | 88° | 88° | 97° | 76–97° |
| 2d · 2026-08-13 | 77° | 78° | 77° | 77° | 81° | 81° | 80° | 77–81° |
| 1d · 2026-08-14 | 77° | 75° | 81° | 78° | 79° | 80° | 84° | 75–84° |
| actual | 84° |
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.