Was the forecast right for San Francisco on Sat Aug 1?
San Francisco, California · daily high temperature · forecasts from each model's archived runs, verified against ERA5
5 days out, 7 models put San Francisco's Sat Aug 1 high anywhere from 66° to 81°; by the final call the field had settled to a median of 76°. ERA5 says the day verified at 71° — partly cloudy.
ECMWF landed closest, off by 1.3°. AIGFS ran 10° hot.
What every model said, at every lead
Daily-high calls for Sat Aug 1 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 |
|---|---|---|---|---|---|---|---|---|
| 5d · 2026-07-27 | 75° | 81° | 70° | 66° | 72° | 66° | 74° | 66–81° |
| 4d · 2026-07-28 | 76° | 78° | 70° | 68° | 73° | 68° | 77° | 68–78° |
| 3d · 2026-07-29 | 78° | 78° | 70° | 68° | 75° | 68° | 78° | 68–78° |
| 2d · 2026-07-30 | 76° | 77° | 71° | 70° | 71° | 66° | 76° | 66–77° |
| 1d · 2026-07-31 | 77° | 80° | 70° | 68° | 77° | 67° | 77° | 67–80° |
| 0d · 2026-08-01 | 76° | 81° | 69° | 68° | 81° | 67° | 76° | 67–81° |
| actual | 71° |
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.