Was the forecast right for San Francisco on Fri Jul 31?
San Francisco, California · daily high temperature · forecasts from each model's archived runs, verified against ERA5
4 days out, 7 models put San Francisco's Fri Jul 31 high anywhere from 64° to 80°; by the final call the field had settled to a median of 73°. ERA5 says the day verified at 69° — clear.
ECMWF landed closest, off by 1.7°. AIGFS ran 6° 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 | 74° | 80° | 67° | 64° | 74° | 65° | 68° | 64–80° |
| 3d · 2026-07-28 | 75° | 78° | 68° | 66° | 74° | 66° | 76° | 66–78° |
| 2d · 2026-07-29 | 74° | 76° | 69° | 67° | 70° | 65° | 76° | 65–76° |
| 1d · 2026-07-30 | 73° | 75° | 68° | 67° | 75° | 64° | 73° | 64–75° |
| 0d · 2026-07-31 | 73° | 75° | 67° | 66° | 73° | 64° | 73° | 64–75° |
| 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 ERA5 reanalysis (temperature_2m_max). Archive depth varies by city; receipts exist only for dates the archive watched arrive.