Was the forecast right for Seattle on Tue Aug 18?
Seattle, Washington · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
14 days out, 4 models put Seattle's Tue Aug 18 high anywhere from 71° to 82°;by the final call, the day before, the field had settled to a median of 79°. The day verified at 82° against the ECMWF IFS analysis — cloudy.
GFS landed closest, off by 1.4°. AIFS ran 8° cool.
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 Seattle scoreboard shows them, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-03 | — | 69° | — | — | 87° | — | — | 69–87° |
| 14d · 2026-08-04 | 71° | 79° | 82° | — | 80° | — | — | 71–82° |
| 13d · 2026-08-05 | 76° | 75° | 81° | — | 72° | — | — | 72–81° |
| 12d · 2026-08-06 | 66° | 71° | 80° | — | 88° | — | — | 66–88° |
| 11d · 2026-08-07 | 72° | 72° | 86° | — | 83° | — | — | 72–86° |
| 10d · 2026-08-08 | 67° | 69° | 68° | — | 79° | — | — | 67–79° |
| 9d · 2026-08-09 | 68° | 79° | 65° | 75° | 63° | — | — | 63–79° |
| 8d · 2026-08-10 | 71° | 81° | 84° | 77° | 80° | — | — | 71–84° |
| 7d · 2026-08-11 | 70° | 76° | 78° | 70° | 89° | 76° | — | 70–89° |
| 6d · 2026-08-12 | 74° | 70° | 77° | 76° | 81° | 67° | 74° | 67–81° |
| 5d · 2026-08-13 | 73° | 76° | 73° | 75° | 81° | 76° | 82° | 73–82° |
| 4d · 2026-08-14 | 71° | 78° | 78° | 74° | 84° | 74° | 81° | 71–84° |
| 3d · 2026-08-15 | 71° | 80° | 78° | 75° | 84° | 75° | 80° | 71–84° |
| 2d · 2026-08-16 | 74° | 81° | 79° | 78° | 83° | 76° | 80° | 74–83° |
| 1d · 2026-08-17 | 74° | 80° | 79° | 78° | 80° | 76° | 80° | 74–80° |
| actual | 82° |
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 ECMWF IFS analysis (temperature_2m_max). 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.