Was the forecast right for San Francisco on Sun Sep 6?
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 Sun Sep 6 high anywhere from 69° to 73°; by the final call the field had settled to a median of 68°. The day verified at 69° against the SFOC1 observations — clear.
AIFS landed closest, off by 0.4°. ICON ran 5° cold.
What every model said, at every lead
Daily-high calls for Sun Sep 6 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 · 2026-08-22 | — | 83° | — | — | 76° | — | — | 76–83° |
| 14d · 2026-08-23 | 74° | 71° | — | — | 67° | — | — | 67–74° |
| 13d · 2026-08-24 | 69° | 72° | 70° | — | 73° | — | — | 69–73° |
| 12d · 2026-08-25 | 72° | 96° | 67° | — | 77° | — | — | 67–96° |
| 11d · 2026-08-26 | 67° | 71° | 65° | — | 68° | — | — | 65–71° |
| 10d · 2026-08-27 | 72° | 67° | 64° | — | 80° | — | — | 64–80° |
| 9d · 2026-08-28 | 77° | 83° | 73° | — | 68° | — | — | 68–83° |
| 8d · 2026-08-29 | 73° | 76° | 66° | 73° | 73° | — | — | 66–76° |
| 7d · 2026-08-30 | 70° | 70° | 70° | 67° | 68° | — | — | 67–70° |
| 6d · 2026-08-31 | 72° | 68° | 66° | 66° | 71° | 80° | — | 66–80° |
| 5d · 2026-09-01 | 69° | 68° | 66° | 64° | 67° | 64° | 69° | 64–69° |
| 4d · 2026-09-02 | 69° | 68° | 65° | 63° | 66° | 64° | 72° | 63–72° |
| 3d · 2026-09-03 | 68° | 67° | 64° | 63° | 67° | 63° | 67° | 63–68° |
| 2d · 2026-09-04 | 68° | 68° | 64° | 64° | 66° | 62° | 70° | 62–70° |
| 1d · 2026-09-05 | 69° | 70° | 67° | 65° | 67° | 65° | 73° | 65–73° |
| 0d · 2026-09-06 | 69° | 71° | 67° | 65° | 68° | 64° | 72° | 64–72° |
| actual | 69° |
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.