Was the forecast right for San Francisco on Thu Sep 10?
San Francisco, California · daily high temperature in °C · forecasts from each model's archived runs, verified against the SFOC1 observations
14 days out, 4 models put San Francisco's Thu Sep 10 high anywhere from 17° to 29°;by the final call, the day before, the field had settled to a median of 23°. The day verified at 24° against the SFOC1 observations — cloudy.
UKMO landed closest, off by 1.1°. AIGFS ran 4° warm.
What every model said, at every lead
Daily-high calls for Thu Sep 10 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, labeled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-26 | — | 18° | — | — | 17° | — | — | 17–18° |
| 14d · 2026-08-27 | 25° | 29° | 17° | — | 23° | — | — | 17–29° |
| 13d · 2026-08-28 | 26° | 30° | 18° | — | 21° | — | — | 18–30° |
| 12d · 2026-08-29 | 26° | 29° | 20° | — | 22° | — | — | 20–29° |
| 11d · 2026-08-30 | 20° | 20° | 21° | — | 26° | — | — | 20–26° |
| 10d · 2026-08-31 | 20° | 22° | 17° | — | 24° | — | — | 17–24° |
| 9d · 2026-09-01 | 19° | 22° | 19° | 21° | 22° | — | — | 19–22° |
| 8d · 2026-09-02 | 19° | 21° | 22° | 20° | 18° | — | — | 18–22° |
| 7d · 2026-09-03 | 28° | 31° | 24° | 18° | 19° | — | — | 18–31° |
| 6d · 2026-09-04 | 29° | 27° | 26° | 18° | 30° | 17° | — | 17–30° |
| 5d · 2026-09-05 | 30° | 33° | 24° | 29° | 28° | 27° | 26° | 24–33° |
| 4d · 2026-09-06 | 29° | 30° | 22° | 22° | 28° | 24° | 26° | 22–30° |
| 3d · 2026-09-07 | 28° | 30° | 22° | 22° | 25° | 23° | 25° | 22–30° |
| 2d · 2026-09-08 | 26° | 29° | 22° | 22° | 25° | 21° | 24° | 21–29° |
| 1d · 2026-09-09 | 27° | 28° | 23° | 22° | 26° | 22° | 23° | 22–28° |
| actual | 24° |
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. 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.