Was the forecast right for Seattle on Sun Sep 20?
Seattle, Washington · daily high temperature in °F · forecasts from each model's archived runs, verified against the SEA observations
14 days out, 4 models put Seattle's Sun Sep 20 high anywhere from 62° to 84°; by the final call the field had settled to a median of 70°. The day verified at 70° against the SEA observations — cloudy.
GEM landed closest, off by 0.4°. GFS ran 4° warm.
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 Seattle scoreboard shows them, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-09-05 | — | 81° | — | — | 71° | — | — | 71–81° |
| 14d · 2026-09-06 | 62° | 66° | 64° | — | 84° | — | — | 62–84° |
| 13d · 2026-09-07 | 65° | 65° | 64° | — | 72° | — | — | 64–72° |
| 12d · 2026-09-08 | 62° | 85° | 74° | — | 68° | — | — | 62–85° |
| 11d · 2026-09-09 | 66° | 72° | 68° | — | 75° | — | — | 66–75° |
| 10d · 2026-09-10 | 66° | 60° | 67° | — | 79° | — | — | 60–79° |
| 9d · 2026-09-11 | 65° | 62° | 68° | 69° | 74° | — | — | 62–74° |
| 8d · 2026-09-12 | 67° | 66° | 71° | 67° | 68° | — | — | 66–71° |
| 7d · 2026-09-13 | 66° | 67° | 66° | 71° | 77° | — | — | 66–77° |
| 6d · 2026-09-14 | 69° | 68° | 66° | 73° | 75° | 70° | 70° | 66–75° |
| 5d · 2026-09-15 | 65° | 67° | 68° | 71° | 76° | 66° | 72° | 65–76° |
| 4d · 2026-09-16 | 67° | 74° | 66° | 72° | 76° | 69° | 72° | 66–76° |
| 3d · 2026-09-17 | 66° | 74° | 67° | 75° | 77° | 71° | 72° | 66–77° |
| 2d · 2026-09-18 | 66° | 73° | 68° | 74° | 76° | 69° | 72° | 66–76° |
| 1d · 2026-09-19 | 65° | 73° | 67° | 74° | 76° | 68° | 72° | 65–76° |
| 0d · 2026-09-20 | 66° | 71° | 66° | 70° | 74° | 66° | 71° | 66–74° |
| actual | 70° |
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 Seattle — 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 SEA observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.