Was the forecast right for San Francisco on Fri Jul 31?
San Francisco, California · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
4 days out, 7 models put San Francisco's Fri Jul 31 high anywhere from 18° to 26°; by the final call the field had settled to a median of 23°. The day verified at 20° against the ECMWF IFS analysis — clear.
ECMWF landed closest, off by 0.9°. AIGFS ran 3° hot.
What every model said, at every lead
Daily-high calls for Fri Jul 31 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 |
|---|---|---|---|---|---|---|---|---|
| 4d · 2026-07-27 | 24° | 26° | 20° | 18° | 23° | 18° | 20° | 18–26° |
| 3d · 2026-07-28 | 24° | 26° | 20° | 19° | 24° | 19° | 24° | 19–26° |
| 2d · 2026-07-29 | 23° | 25° | 20° | 19° | 21° | 18° | 25° | 18–25° |
| 1d · 2026-07-30 | 23° | 24° | 20° | 20° | 24° | 18° | 23° | 18–24° |
| 0d · 2026-07-31 | 23° | 24° | 20° | 19° | 23° | 18° | 23° | 18–24° |
| actual | 20° |
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). Archive depth varies by city; receipts exist only for dates the archive watched arrive.