Was the forecast right for Chicago on Sun Aug 16?
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 16 high anywhere from 72° to 83°;by the final call, the day before, the field had settled to a median of 85°. The day verified at 88° against the ECMWF IFS analysis, with 0.35 in of precipitation — thunderstorms.
GEM landed closest, off by 0.7°. AIFS ran 6° cool.
What every model said, at every lead
Daily-high calls for Sun Aug 16 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 · 2026-08-01 | — | 83° | — | — | 86° | — | — | 83–86° |
| 14d · 2026-08-02 | 83° | 80° | 81° | — | 72° | — | — | 72–83° |
| 13d · 2026-08-03 | 74° | 71° | 73° | — | 76° | — | — | 71–76° |
| 12d · 2026-08-04 | 76° | 77° | 73° | — | 76° | — | — | 73–77° |
| 11d · 2026-08-05 | 81° | 74° | 75° | — | 76° | — | — | 74–81° |
| 10d · 2026-08-06 | 68° | 65° | 72° | — | 79° | — | — | 65–79° |
| 9d · 2026-08-07 | 76° | 79° | 82° | 75° | 72° | — | — | 72–82° |
| 8d · 2026-08-08 | 80° | 76° | 78° | 72° | 74° | — | — | 72–80° |
| 7d · 2026-08-09 | 82° | 80° | 76° | 83° | 82° | — | — | 76–83° |
| 6d · 2026-08-10 | 82° | 80° | 82° | 75° | 86° | 79° | 86° | 75–86° |
| 5d · 2026-08-11 | 83° | 84° | 87° | 85° | 79° | 86° | 87° | 79–87° |
| 4d · 2026-08-12 | 82° | 82° | 84° | 79° | 82° | 83° | 86° | 79–86° |
| 3d · 2026-08-13 | 82° | 84° | 82° | 87° | 84° | 81° | 80° | 80–87° |
| 2d · 2026-08-14 | 81° | 84° | 83° | 80° | 84° | 82° | 88° | 80–88° |
| 1d · 2026-08-15 | 82° | 85° | 84° | 88° | 84° | 86° | 90° | 82–90° |
| actual | 88° |
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.