Was the forecast right for Seattle on Fri Sep 11?
Seattle, Washington · daily high temperature in °C · forecasts from each model's archived runs, verified against the SEA observations
14 days out, 4 models put Seattle's Fri Sep 11 high anywhere from 15° to 20°;by the final call, the day before, the field had settled to a median of 20°. The day verified at 19° against the SEA observations — drizzle.
ECMWF landed closest, off by 0.4°. GEM ran 2° warm.
What every model said, at every lead
Daily-high calls for Fri Sep 11 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, labeled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-27 | — | 16° | — | — | 29° | — | — | 16–29° |
| 14d · 2026-08-28 | 18° | 15° | 20° | — | 17° | — | — | 15–20° |
| 13d · 2026-08-29 | 21° | 22° | 20° | — | 25° | — | — | 20–25° |
| 12d · 2026-08-30 | 25° | 22° | 22° | — | 28° | — | — | 22–28° |
| 11d · 2026-08-31 | 20° | 25° | 16° | — | 18° | — | — | 16–25° |
| 10d · 2026-09-01 | 19° | 17° | 22° | — | 17° | — | — | 17–22° |
| 9d · 2026-09-02 | 16° | 16° | 22° | 16° | 22° | — | — | 16–22° |
| 8d · 2026-09-03 | 20° | 26° | 16° | 19° | 26° | — | — | 16–26° |
| 7d · 2026-09-04 | 20° | 17° | 21° | 26° | 22° | 22° | — | 17–26° |
| 6d · 2026-09-05 | 18° | 16° | 20° | 21° | 19° | 18° | 20° | 16–21° |
| 5d · 2026-09-06 | 18° | 19° | 19° | 20° | 17° | 19° | 20° | 17–20° |
| 4d · 2026-09-07 | 19° | 21° | 19° | 18° | 19° | 19° | 18° | 18–21° |
| 3d · 2026-09-08 | 18° | 19° | 18° | 18° | 19° | 20° | 19° | 18–20° |
| 2d · 2026-09-09 | 18° | 19° | 19° | 20° | 20° | 19° | 20° | 18–20° |
| 1d · 2026-09-10 | 19° | 20° | 20° | 21° | 20° | 19° | 20° | 19–21° |
| actual | 19° |
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. The actual values are the ones in hand when this day was verified, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; verified days exist only for dates the archive watched arrive.