Was the forecast right for San Francisco on Tue Aug 4?
San Francisco, California · daily high temperature · forecasts from each model's archived runs, verified against ERA5
8 days out, 5 models put San Francisco's Tue Aug 4 high anywhere from 66° to 85°; by the final call the field had settled to a median of 71°. ERA5 says the day verified at 67° — cloudy.
ICON landed closest, off by 2.5°. AIGFS ran 11° hot.
What every model said, at every lead
Daily-high calls for Tue Aug 4 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 · 2026-07-27 | 68° | 77° | 69° | 66° | 85° | — | — | 66–85° |
| 7d · 2026-07-28 | 72° | 72° | 63° | 67° | 80° | — | — | 63–80° |
| 6d · 2026-07-29 | 72° | 75° | 65° | 68° | 78° | 63° | — | 63–78° |
| 5d · 2026-07-30 | 72° | 78° | 65° | 71° | 76° | 63° | 65° | 63–78° |
| 4d · 2026-07-31 | 72° | 78° | 67° | 71° | 79° | 65° | 67° | 65–79° |
| 3d · 2026-08-01 | 71° | 78° | 68° | 70° | 77° | 64° | 68° | 64–78° |
| 2d · 2026-08-02 | 71° | 79° | 69° | 74° | 78° | 66° | 69° | 66–79° |
| 1d · 2026-08-03 | 70° | 79° | 69° | 72° | 71° | 66° | 70° | 66–79° |
| 0d · 2026-08-04 | 71° | 78° | 70° | 70° | 72° | 65° | 72° | 65–78° |
| actual | 67° |
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.