Was the forecast right for Chicago on Tue Sep 29?
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 Tue Sep 29 high anywhere from 66° to 79°;by the final call, the day before, the field had settled to a median of 76°. The day verified at 80° against the MDW observations — cloudy.
GEM landed closest, off by 0.4°. AIFS ran 6° cool.
What every model said, at every lead
Daily-high calls for Tue Sep 29 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 · 2026-09-14 | — | 73° | — | — | 67° | — | — | 67–73° |
| 14d · 2026-09-15 | 78° | 66° | 79° | — | 79° | — | — | 66–79° |
| 13d · 2026-09-16 | 68° | 63° | 71° | — | 80° | — | — | 63–80° |
| 12d · 2026-09-17 | 72° | 75° | 63° | — | 78° | — | — | 63–78° |
| 11d · 2026-09-18 | 74° | 64° | 68° | — | 52° | — | — | 52–74° |
| 10d · 2026-09-19 | 75° | 73° | 74° | — | 76° | — | — | 73–76° |
| 9d · 2026-09-20 | 66° | 65° | 74° | 69° | 78° | — | — | 65–78° |
| 8d · 2026-09-21 | 73° | 74° | 73° | 66° | 76° | — | — | 66–76° |
| 7d · 2026-09-22 | 73° | 80° | 70° | 74° | 79° | — | — | 70–80° |
| 6d · 2026-09-23 | 72° | 77° | 71° | 73° | 74° | 75° | 70° | 70–77° |
| 5d · 2026-09-24 | 75° | 76° | 76° | 73° | 73° | 73° | 77° | 73–77° |
| 4d · 2026-09-25 | 75° | 77° | 74° | 73° | 74° | 74° | 72° | 72–77° |
| 3d · 2026-09-26 | 74° | 77° | 74° | 76° | 78° | 75° | 75° | 74–78° |
| 2d · 2026-09-27 | 74° | 76° | 74° | 77° | 78° | 76° | 75° | 74–78° |
| 1d · 2026-09-28 | 74° | 75° | 74° | 80° | 77° | 76° | 76° | 74–80° |
| actual | 80° |
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.