Was the forecast right for Denver on Sun Sep 20?
Denver, Colorado · daily high temperature in °F · forecasts from each model's archived runs, verified against the DEN observations
13 days out, 4 models put Denver's Sun Sep 20 high anywhere from 69° to 85°; by the final call the field had settled to a median of 70°. The day verified at 74° against the DEN observations, with 0.12 in of precipitation — drizzle.
ICON landed closest, off by 2.4°. GEM ran 5° cool.
What every model said, at every lead
Daily-high calls for Sun Sep 20 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 Denver scoreboard shows them, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-09-05 | — | 78° | — | — | 84° | — | — | 78–84° |
| 14d · 2026-09-06 | 82° | 56° | — | — | 84° | — | — | 56–84° |
| 13d · 2026-09-07 | 83° | 85° | 69° | — | 79° | — | — | 69–85° |
| 12d · 2026-09-08 | 61° | 72° | 64° | — | 83° | — | — | 61–83° |
| 11d · 2026-09-09 | 82° | 68° | 75° | — | 85° | — | — | 68–85° |
| 10d · 2026-09-10 | 77° | 85° | 84° | — | 78° | — | — | 77–85° |
| 9d · 2026-09-11 | 76° | 81° | 66° | — | 86° | — | — | 66–86° |
| 8d · 2026-09-12 | 79° | 77° | 74° | 78° | 76° | — | — | 74–79° |
| 7d · 2026-09-13 | 76° | 82° | 70° | 76° | 76° | — | — | 70–82° |
| 6d · 2026-09-14 | 70° | 74° | 71° | 71° | 74° | 78° | — | 70–78° |
| 5d · 2026-09-15 | 68° | 74° | 73° | 62° | 72° | 76° | 80° | 62–80° |
| 4d · 2026-09-16 | 71° | 69° | 73° | 64° | 74° | 74° | 70° | 64–74° |
| 3d · 2026-09-17 | 67° | 68° | 67° | 62° | 76° | 72° | 72° | 62–76° |
| 2d · 2026-09-18 | 70° | 68° | 69° | 68° | 71° | 71° | 77° | 68–77° |
| 1d · 2026-09-19 | 68° | 69° | 69° | 67° | 72° | 70° | 68° | 67–72° |
| 0d · 2026-09-20 | 71° | 70° | 69° | 69° | 70° | 72° | 70° | 69–72° |
| actual | 74° |
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 Denver — 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 DEN observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.