Was the forecast right for San Francisco on Mon Aug 3?
San Francisco, California · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
8 days out, 5 models put San Francisco's Mon Aug 3 high anywhere from 18° to 25°;by the final call, the day before, the field had settled to a median of 24°. The day verified at 21° against the ECMWF IFS analysis — partly cloudy.
ICON landed closest, off by 1.3°. GFS ran 8° warm.
What every model said, at every lead
Daily-high calls for Mon Aug 3 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 |
|---|---|---|---|---|---|---|---|---|
| 8d · 2026-07-26 | 23° | 25° | 18° | 18° | 25° | — | — | 18–25° |
| 7d · 2026-07-27 | 23° | 24° | 18° | 20° | 26° | — | — | 18–26° |
| 6d · 2026-07-28 | 23° | 23° | 18° | 18° | 27° | 18° | 21° | 18–27° |
| 5d · 2026-07-29 | 24° | 25° | 22° | 21° | 27° | 18° | 26° | 18–27° |
| 4d · 2026-07-30 | 24° | 27° | 22° | 22° | 26° | 19° | 23° | 19–27° |
| 3d · 2026-07-31 | 25° | 29° | 22° | 24° | 28° | 19° | 25° | 19–29° |
| 2d · 2026-08-01 | 24° | 28° | 22° | 24° | 26° | 19° | 24° | 19–28° |
| 1d · 2026-08-02 | 24° | 29° | 23° | 24° | 29° | 19° | 24° | 19–29° |
| actual | 21° |
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 ECMWF IFS analysis (temperature_2m_max). 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.