Was the forecast right for Denver on Tue Aug 18?
Denver, Colorado · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
13 days out, 4 models put Denver's Tue Aug 18 high anywhere from 79° to 87°; by the final call the field had settled to a median of 91°. The day verified at 89° against the ECMWF IFS analysis — drizzle.
AIGFS landed closest, off by 1.3°. GFS ran 5° hot.
What every model said, at every lead
Daily-high calls for Tue Aug 18 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 · 2026-08-03 | — | 81° | — | — | 95° | — | — | 81–95° |
| 14d · 2026-08-04 | 82° | 73° | — | — | 100° | — | — | 73–100° |
| 13d · 2026-08-05 | 79° | 80° | 82° | — | 87° | — | — | 79–87° |
| 12d · 2026-08-06 | 79° | 84° | 80° | — | 94° | — | — | 79–94° |
| 11d · 2026-08-07 | 76° | 88° | 78° | — | 74° | — | — | 74–88° |
| 10d · 2026-08-08 | 82° | 90° | 84° | — | 96° | — | — | 82–96° |
| 9d · 2026-08-09 | 80° | 76° | 87° | — | 94° | — | — | 76–94° |
| 8d · 2026-08-10 | 86° | 93° | 84° | 94° | 90° | — | — | 84–94° |
| 7d · 2026-08-11 | 84° | 92° | 92° | 89° | 92° | — | — | 84–92° |
| 6d · 2026-08-12 | 87° | 91° | 94° | 88° | 96° | 93° | — | 87–96° |
| 5d · 2026-08-13 | 88° | 83° | 91° | 93° | 93° | 89° | 90° | 83–93° |
| 4d · 2026-08-14 | 91° | 86° | 95° | 92° | 94° | 89° | 90° | 86–95° |
| 3d · 2026-08-15 | 92° | 91° | 96° | 90° | 98° | 94° | 90° | 90–98° |
| 2d · 2026-08-16 | 92° | 92° | 96° | 90° | 96° | 93° | 88° | 88–96° |
| 1d · 2026-08-17 | 88° | 88° | 87° | 91° | 92° | 94° | 89° | 87–94° |
| 0d · 2026-08-18 | 84° | 88° | 87° | 92° | 94° | 94° | 91° | 84–94° |
| actual | 89° |
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 ECMWF IFS analysis (temperature_2m_max). Archive depth varies by city; receipts exist only for dates the archive watched arrive.