Was the forecast right for Denver on Mon Sep 21?
Denver, Colorado · daily high temperature in °F · forecasts from each model's archived runs, verified against the DEN observations
14 days out, 4 models put Denver's Mon Sep 21 high anywhere from 66° to 84°;by the final call, the day before, the field had settled to a median of 73°. The day verified at 75° against the DEN observations — drizzle.
GEM landed closest, off by 0.5°. AIGFS ran 4° cool.
What every model said, at every lead
Daily-high calls for Mon Sep 21 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 · 2026-09-06 | — | 65° | — | — | 85° | — | — | 65–85° |
| 14d · 2026-09-07 | 66° | 77° | 84° | — | 80° | — | — | 66–84° |
| 13d · 2026-09-08 | 73° | 76° | 83° | — | 71° | — | — | 71–83° |
| 12d · 2026-09-09 | 74° | 79° | 72° | — | 86° | — | — | 72–86° |
| 11d · 2026-09-10 | 66° | 82° | 75° | — | 82° | — | — | 66–82° |
| 10d · 2026-09-11 | 76° | 75° | 75° | — | 80° | — | — | 75–80° |
| 9d · 2026-09-12 | 82° | 71° | 79° | 76° | 76° | — | — | 71–82° |
| 8d · 2026-09-13 | 69° | 70° | 63° | 70° | 75° | — | — | 63–75° |
| 7d · 2026-09-14 | 69° | 75° | 71° | 74° | 78° | — | — | 69–78° |
| 6d · 2026-09-15 | 74° | 74° | 72° | 72° | 79° | 78° | 73° | 72–79° |
| 5d · 2026-09-16 | 73° | 71° | 71° | 72° | 76° | 76° | 72° | 71–76° |
| 4d · 2026-09-17 | 71° | 69° | 70° | 70° | 78° | 68° | 70° | 68–78° |
| 3d · 2026-09-18 | 70° | 70° | 69° | 73° | 78° | 75° | 77° | 69–78° |
| 2d · 2026-09-19 | 72° | 70° | 71° | 72° | 76° | 74° | 70° | 70–76° |
| 1d · 2026-09-20 | 73° | 71° | 73° | 74° | 74° | 73° | 71° | 71–74° |
| actual | 75° |
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.