Was the forecast right for Chicago on Sun Sep 27?
Chicago, Illinois · daily high temperature in °C · forecasts from each model's archived runs, verified against the MDW observations
13 days out, 4 models put Chicago's Sun Sep 27 high anywhere from 19° to 26°;by the final call, the day before, the field had settled to a median of 21°. The day verified at 22° against the MDW observations — cloudy.
GFS landed closest, off by 0.1°. UKMO ran 2° cool.
What every model said, at every lead
Daily-high calls for Sun Sep 27 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 · 2026-09-12 | — | 22° | — | — | 27° | — | — | 22–27° |
| 14d · 2026-09-13 | 24° | 27° | — | — | 25° | — | — | 24–27° |
| 13d · 2026-09-14 | 19° | 23° | 26° | — | 26° | — | — | 19–26° |
| 12d · 2026-09-15 | 22° | 17° | 23° | — | 26° | — | — | 17–26° |
| 11d · 2026-09-16 | 21° | 19° | 19° | — | 22° | — | — | 19–22° |
| 10d · 2026-09-17 | 21° | 24° | 20° | — | 24° | — | — | 20–24° |
| 9d · 2026-09-18 | 22° | 17° | 20° | 19° | 25° | — | — | 17–25° |
| 8d · 2026-09-19 | 22° | 23° | 21° | 20° | 22° | — | — | 20–23° |
| 7d · 2026-09-20 | 21° | 19° | 20° | 21° | 23° | — | — | 19–23° |
| 6d · 2026-09-21 | 21° | 21° | 19° | 21° | 21° | 20° | 20° | 19–21° |
| 5d · 2026-09-22 | 21° | 23° | 20° | 20° | 24° | 21° | 21° | 20–24° |
| 4d · 2026-09-23 | 21° | 23° | 20° | 20° | 23° | 18° | 20° | 18–23° |
| 3d · 2026-09-24 | 22° | 22° | 20° | 20° | 23° | 22° | 20° | 20–23° |
| 2d · 2026-09-25 | 21° | 22° | 20° | 21° | 22° | 22° | 20° | 20–22° |
| 1d · 2026-09-26 | 21° | 21° | 20° | 23° | 22° | 22° | 20° | 20–23° |
| actual | 22° |
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.