The Spread

Was the forecast right for San Francisco on Tue Aug 11?

San Francisco, California · daily high temperature in °F · forecasts from each model's archived runs, verified against ERA5

13 days out, 4 models put San Francisco's Tue Aug 11 high anywhere from 64° to 71°; by the final call the field had settled to a median of 68°. ERA5 says the day verified at 65° — cloudy.

GFS landed closest, off by 0.6°. AIGFS ran 7° hot.

13 days out the models said 64–71; it hit 65. GFS led (off 0.6°F); AIGFS ran 7°F hot.
The shareable card for this receipt — what this page looks like pasted into a thread.

What every model said, at every lead

Daily-high calls for Tue Aug 11 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 AIFSAIGFSECMWFGEMGFSICONUKMO Range
15d · 2026-07-27 72° 72° 72–72°
14d · 2026-07-28 69° 67° 69° 67–69°
13d · 2026-07-29 70° 71° 64° 66° 64–71°
12d · 2026-07-30 64° 72° 61° 73° 61–73°
11d · 2026-07-31 66° 66° 61° 70° 61–70°
10d · 2026-08-01 64° 72° 64° 79° 64–79°
9d · 2026-08-02 67° 74° 67° 71° 67–74°
8d · 2026-08-03 68° 75° 64° 65° 76° 64–76°
7d · 2026-08-04 70° 76° 68° 68° 68° 68–76°
6d · 2026-08-05 70° 77° 66° 68° 72° 64° 64–77°
5d · 2026-08-06 68° 74° 66° 69° 72° 62° 65° 62–74°
4d · 2026-08-07 69° 71° 68° 70° 73° 63° 66° 63–73°
3d · 2026-08-08 69° 73° 68° 69° 74° 62° 63° 62–74°
2d · 2026-08-09 69° 74° 69° 70° 75° 64° 66° 64–75°
1d · 2026-08-10 69° 72° 69° 70° 67° 64° 68° 64–72°
0d · 2026-08-11 69° 72° 68° 68° 66° 63° 68° 63–72°
actual 65°

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.