Was the forecast right for San Francisco on Fri Sep 4?
San Francisco, California · daily high temperature in °F · forecasts from each model's archived runs, verified against the SFOC1 observations
13 days out, 4 models put San Francisco's Fri Sep 4 high anywhere from 66° to 74°;by the final call, the day before, the field had settled to a median of 68°. The day verified at 68° against the SFOC1 observations — cloudy.
AIFS landed closest, off by 0.3°. GEM ran 3° cool.
What every model said, at every lead
Daily-high calls for Fri Sep 4 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 |
|---|---|---|---|---|---|---|---|---|
| 13d · 2026-08-22 | 74° | 74° | 66° | — | 74° | — | — | 66–74° |
| 12d · 2026-08-23 | 69° | 85° | 62° | — | 71° | — | — | 62–85° |
| 11d · 2026-08-24 | 73° | 72° | 67° | — | 69° | — | — | 67–73° |
| 10d · 2026-08-25 | 77° | 86° | 67° | — | 70° | — | — | 67–86° |
| 9d · 2026-08-26 | 75° | 69° | 64° | 62° | 71° | — | — | 62–75° |
| 8d · 2026-08-27 | 68° | 79° | 68° | 70° | 68° | — | — | 68–79° |
| 7d · 2026-08-28 | 68° | 70° | 67° | 64° | 68° | — | — | 64–70° |
| 6d · 2026-08-29 | 68° | 73° | 64° | 65° | 71° | 64° | 70° | 64–73° |
| 5d · 2026-08-30 | 68° | 71° | 67° | 66° | 65° | 63° | 71° | 63–71° |
| 4d · 2026-08-31 | 68° | 70° | 66° | 65° | 66° | 63° | 68° | 63–70° |
| 3d · 2026-09-01 | 67° | 70° | 65° | 64° | 69° | 67° | 68° | 64–70° |
| 2d · 2026-09-02 | 67° | 69° | 64° | 64° | 68° | 65° | 72° | 64–72° |
| 1d · 2026-09-03 | 68° | 70° | 66° | 65° | 70° | 65° | 70° | 65–70° |
| actual | 68° |
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 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.