Was the forecast right for Chicago on Thu Aug 6?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
11 days out, 4 models put Chicago's Thu Aug 6 high anywhere from 74° to 94°;by the final call, the day before, the field had settled to a median of 76°. The day verified at 78° against the ECMWF IFS analysis, with 0.14 in of precipitation — drizzle.
AIFS landed closest, off by 1.0°. GEM ran 4° cool.
What every model said, at every lead
Daily-high calls for Thu Aug 6 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 |
|---|---|---|---|---|---|---|---|---|
| 11d · 2026-07-26 | 78° | 77° | 94° | — | 74° | — | — | 74–94° |
| 10d · 2026-07-27 | 85° | 78° | 86° | — | 83° | — | — | 78–86° |
| 9d · 2026-07-28 | 81° | 79° | 85° | 75° | 84° | — | — | 75–85° |
| 8d · 2026-07-29 | 76° | 82° | 80° | 80° | 88° | — | — | 76–88° |
| 7d · 2026-07-30 | 76° | 83° | 78° | 86° | 84° | — | — | 76–86° |
| 6d · 2026-07-31 | 77° | 77° | 79° | 80° | 89° | 84° | 78° | 77–89° |
| 5d · 2026-08-01 | 73° | 75° | 72° | 73° | 74° | 82° | 80° | 72–82° |
| 4d · 2026-08-02 | 74° | 75° | 78° | 72° | 71° | 76° | 74° | 71–78° |
| 3d · 2026-08-03 | 77° | 77° | 78° | 70° | 79° | 78° | 72° | 70–79° |
| 2d · 2026-08-04 | 78° | 77° | 78° | 75° | 79° | 76° | 74° | 74–79° |
| 1d · 2026-08-05 | 78° | 77° | 76° | 75° | 76° | 81° | 76° | 75–81° |
| 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.