Was the forecast right for San Francisco on Mon Sep 21?
San Francisco, California · daily high temperature in °F · forecasts from each model's archived runs, verified against the SFOC1 observations
14 days out, 4 models put San Francisco's Mon Sep 21 high anywhere from 65° to 82°;by the final call, the day before, the field had settled to a median of 64°. The day verified at 61° against the SFOC1 observations — cloudy.
UKMO landed closest, off by 0.3°. AIGFS ran 5° warm.
What every model said, at every lead
Daily-high calls for Mon Sep 21 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 · 2026-09-06 | — | 85° | — | — | 67° | — | — | 67–85° |
| 14d · 2026-09-07 | 82° | 65° | 65° | — | 67° | — | — | 65–82° |
| 13d · 2026-09-08 | 74° | 66° | 63° | — | 73° | — | — | 63–74° |
| 12d · 2026-09-09 | 80° | 90° | 70° | — | 79° | — | — | 70–90° |
| 11d · 2026-09-10 | 70° | 80° | 64° | — | 75° | — | — | 64–80° |
| 10d · 2026-09-11 | 76° | 78° | 63° | — | 65° | — | — | 63–78° |
| 9d · 2026-09-12 | 71° | 72° | 66° | — | 65° | — | — | 65–72° |
| 8d · 2026-09-13 | 63° | 73° | 63° | 63° | 69° | — | — | 63–73° |
| 7d · 2026-09-14 | 65° | 73° | 62° | 62° | 72° | — | — | 62–73° |
| 6d · 2026-09-15 | 66° | 73° | 62° | 64° | 70° | 67° | 61° | 61–73° |
| 5d · 2026-09-16 | 65° | 69° | 63° | 62° | 66° | 63° | 62° | 62–69° |
| 4d · 2026-09-17 | 66° | 69° | 64° | 62° | 68° | 64° | 62° | 62–69° |
| 3d · 2026-09-18 | 66° | 70° | 64° | 64° | 67° | 63° | 62° | 62–70° |
| 2d · 2026-09-19 | 64° | 68° | 64° | 64° | 69° | 64° | 61° | 61–69° |
| 1d · 2026-09-20 | 64° | 66° | 64° | 64° | 66° | 63° | 61° | 61–66° |
| actual | 61° |
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.