Was the forecast right for Seattle on Tue Sep 1?
Seattle, Washington · daily high temperature in °C · forecasts from each model's archived runs, verified against the SEA observations
9 days out, 5 models put Seattle's Tue Sep 1 high anywhere from 17° to 24°;by the final call, the day before, the field had settled to a median of 21°. The day verified at 19° against the SEA observations — drizzle.
AIFS landed closest, off by 0.2°. GFS ran 6° warm.
What every model said, at every lead
Daily-high calls for Tue Sep 1 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 |
|---|---|---|---|---|---|---|---|---|
| 9d · 2026-08-23 | 19° | 20° | 22° | 17° | 24° | — | — | 17–24° |
| 8d · 2026-08-24 | 17° | 18° | 20° | 21° | 17° | — | — | 17–21° |
| 7d · 2026-08-25 | 20° | 20° | 21° | 19° | 21° | 22° | — | 19–22° |
| 6d · 2026-08-26 | 21° | 23° | 18° | 22° | 22° | 22° | 19° | 18–23° |
| 5d · 2026-08-27 | 21° | 24° | 21° | 23° | 26° | 20° | 19° | 19–26° |
| 4d · 2026-08-28 | 19° | 22° | 22° | 22° | 23° | 22° | 23° | 19–23° |
| 3d · 2026-08-29 | 20° | 22° | 23° | 21° | 27° | 23° | 24° | 20–27° |
| 2d · 2026-08-30 | 20° | 20° | 23° | 22° | 26° | 21° | 23° | 20–26° |
| 1d · 2026-08-31 | 19° | 20° | 21° | 22° | 25° | 21° | 22° | 19–25° |
| 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 receipt was settled, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; receipts exist only for dates the archive watched arrive.