Was the forecast right for Chicago on Thu Aug 13?
Chicago, Illinois · daily high temperature in °F · forecasts from each model's archived runs, verified against ERA5
13 days out, 4 models put Chicago's Thu Aug 13 high anywhere from 71° to 83°; by the final call the field had settled to a median of 76°. ERA5 says the day verified at 79° with 0.6 in of precipitation — rain.
ICON landed closest, off by 1.0°. AIFS ran 4° cold.
What every model said, at every lead
Daily-high calls for Thu Aug 13 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 · 2026-07-29 | — | 77° | — | — | 88° | — | — | 77–88° |
| 14d · 2026-07-30 | 81° | 73° | — | — | 77° | — | — | 73–81° |
| 13d · 2026-07-31 | 83° | 81° | 71° | — | 81° | — | — | 71–83° |
| 12d · 2026-08-01 | 77° | 77° | 80° | — | 75° | — | — | 75–80° |
| 11d · 2026-08-02 | 78° | 78° | 84° | — | 92° | — | — | 78–92° |
| 10d · 2026-08-03 | 79° | 66° | 83° | — | 71° | — | — | 66–83° |
| 9d · 2026-08-04 | 75° | 78° | 73° | — | 70° | — | — | 70–78° |
| 8d · 2026-08-05 | 81° | 72° | 82° | 79° | 81° | — | — | 72–82° |
| 7d · 2026-08-06 | 74° | 82° | 82° | 75° | 71° | — | — | 71–82° |
| 6d · 2026-08-07 | 78° | 75° | 77° | 72° | 75° | 78° | — | 72–78° |
| 5d · 2026-08-08 | 77° | 78° | 80° | 71° | 69° | 75° | 86° | 69–86° |
| 4d · 2026-08-09 | 76° | 75° | 74° | 73° | 73° | 79° | 80° | 73–80° |
| 3d · 2026-08-10 | 76° | 77° | 79° | 72° | 79° | 81° | 80° | 72–81° |
| 2d · 2026-08-11 | 74° | 78° | 75° | 75° | 79° | 79° | 74° | 74–79° |
| 1d · 2026-08-12 | 76° | 77° | 74° | 78° | 77° | 78° | 77° | 74–78° |
| 0d · 2026-08-13 | 75° | 78° | 77° | 76° | 76° | 80° | 76° | 75–80° |
| actual | 79° |
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 ERA5 reanalysis (temperature_2m_max). Archive depth varies by city; receipts exist only for dates the archive watched arrive.