Was the forecast right for Chicago on Sun Sep 27?
Chicago, Illinois · daily high temperature in °F · 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 66° to 79°;by the final call, the day before, the field had settled to a median of 71°. The day verified at 72° against the MDW observations — cloudy.
GFS landed closest, off by 0.2°. UKMO ran 4° 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 | — | 71° | — | — | 81° | — | — | 71–81° |
| 14d · 2026-09-13 | 76° | 81° | — | — | 78° | — | — | 76–81° |
| 13d · 2026-09-14 | 66° | 73° | 79° | — | 78° | — | — | 66–79° |
| 12d · 2026-09-15 | 71° | 62° | 73° | — | 78° | — | — | 62–78° |
| 11d · 2026-09-16 | 70° | 66° | 66° | — | 72° | — | — | 66–72° |
| 10d · 2026-09-17 | 70° | 74° | 69° | — | 76° | — | — | 69–76° |
| 9d · 2026-09-18 | 71° | 62° | 67° | 67° | 78° | — | — | 62–78° |
| 8d · 2026-09-19 | 71° | 74° | 69° | 68° | 71° | — | — | 68–74° |
| 7d · 2026-09-20 | 70° | 66° | 67° | 70° | 74° | — | — | 66–74° |
| 6d · 2026-09-21 | 70° | 70° | 67° | 70° | 70° | 68° | 68° | 67–70° |
| 5d · 2026-09-22 | 70° | 74° | 68° | 68° | 75° | 70° | 70° | 68–75° |
| 4d · 2026-09-23 | 70° | 74° | 69° | 67° | 74° | 65° | 68° | 65–74° |
| 3d · 2026-09-24 | 71° | 72° | 69° | 69° | 74° | 71° | 68° | 68–74° |
| 2d · 2026-09-25 | 71° | 72° | 69° | 70° | 72° | 71° | 69° | 69–72° |
| 1d · 2026-09-26 | 71° | 70° | 68° | 73° | 72° | 71° | 68° | 68–73° |
| actual | 72° |
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.