Was the forecast right for San Francisco on Wed Sep 9?
San Francisco, California · daily high temperature in °C · forecasts from each model's archived runs, verified against the SFOC1 observations
13 days out, 4 models put San Francisco's Wed Sep 9 high anywhere from 17° to 23°; by the final call the field had settled to a median of 31°. The day verified at 34° against the SFOC1 observations — cloudy.
UKMO landed closest, off by 0.2°. GEM ran 6° cold.
What every model said, at every lead
Daily-high calls for Wed Sep 9 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 San Francisco scoreboard shows them, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-25 | — | 18° | — | — | 21° | — | — | 18–21° |
| 14d · 2026-08-26 | 21° | 17° | — | — | 22° | — | — | 17–22° |
| 13d · 2026-08-27 | 21° | 22° | 17° | — | 23° | — | — | 17–23° |
| 12d · 2026-08-28 | 27° | 31° | 17° | — | 21° | — | — | 17–31° |
| 11d · 2026-08-29 | 21° | 26° | 16° | — | 27° | — | — | 16–27° |
| 10d · 2026-08-30 | 23° | 27° | 21° | — | 24° | — | — | 21–27° |
| 9d · 2026-08-31 | 26° | 23° | 30° | — | 24° | — | — | 23–30° |
| 8d · 2026-09-01 | 20° | 21° | 18° | 20° | 28° | — | — | 18–28° |
| 7d · 2026-09-02 | 22° | 24° | 19° | 17° | 18° | — | — | 17–24° |
| 6d · 2026-09-03 | 27° | 19° | 18° | 16° | 20° | 21° | — | 16–27° |
| 5d · 2026-09-04 | 33° | 34° | 20° | 16° | 21° | 18° | 22° | 16–34° |
| 4d · 2026-09-05 | 33° | 35° | 28° | 26° | 28° | 31° | 29° | 26–35° |
| 3d · 2026-09-06 | 32° | 35° | 31° | 26° | 30° | 27° | 34° | 26–35° |
| 2d · 2026-09-07 | 31° | 34° | 28° | 26° | 30° | 29° | 35° | 26–35° |
| 1d · 2026-09-08 | 31° | 34° | 31° | 28° | 32° | 30° | 36° | 28–36° |
| 0d · 2026-09-09 | 31° | 34° | 31° | 28° | 31° | 29° | 34° | 28–34° |
| actual | 34° |
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 San Francisco — 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 SFOC1 observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.