Was the forecast right for Seattle on Thu Sep 3?
Seattle, Washington · daily high temperature in °C · forecasts from each model's archived runs, verified against the SEA observations
11 days out, 4 models put Seattle's Thu Sep 3 high anywhere from 15° to 19°;by the final call, the day before, the field had settled to a median of 18°. The day verified at 20° against the SEA observations, with 3.0 mm of precipitation — showers.
GFS landed closest, off by 1.9°. GEM ran 3° cool.
What every model said, at every lead
Daily-high calls for Thu Sep 3 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 |
|---|---|---|---|---|---|---|---|---|
| 11d · 2026-08-23 | 18° | 19° | 18° | — | 15° | — | — | 15–19° |
| 10d · 2026-08-24 | 20° | 18° | 20° | — | 25° | — | — | 18–25° |
| 9d · 2026-08-25 | 20° | 18° | 19° | 16° | 14° | — | — | 14–20° |
| 8d · 2026-08-26 | 17° | 14° | 16° | 20° | 14° | — | — | 14–20° |
| 7d · 2026-08-27 | 18° | 15° | 17° | 14° | 20° | 21° | — | 14–21° |
| 6d · 2026-08-28 | 19° | 20° | 19° | 14° | 14° | 16° | 19° | 14–20° |
| 5d · 2026-08-29 | 16° | 22° | 15° | 18° | 23° | 16° | 17° | 15–23° |
| 4d · 2026-08-30 | 16° | 18° | 17° | 17° | 16° | 19° | 16° | 16–19° |
| 3d · 2026-08-31 | 18° | 17° | 18° | 20° | 22° | 18° | 19° | 17–22° |
| 2d · 2026-09-01 | 17° | 17° | 16° | 19° | 19° | 17° | 17° | 16–19° |
| 1d · 2026-09-02 | 17° | 18° | 18° | 17° | 18° | 18° | 18° | 17–18° |
| actual | 20° |
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.