The Spread

Was the forecast right for San Francisco on Thu Jul 30?

San Francisco, California · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis

3 days out, 7 models put San Francisco's Thu Jul 30 high anywhere from 18° to 25°; by the final call the field had settled to a median of 21°. The day verified at 18° against the ECMWF IFS analysis — clear.

GEM landed closest, off by 0.2°. AIGFS ran 5° hot.

3 days out the models said 18–25; it hit 18. GEM led (off 0.2°C); AIGFS ran 5°C 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 Thu Jul 30 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
3d · 2026-07-27 21° 25° 19° 18° 21° 18° 22° 18–25°
2d · 2026-07-28 21° 22° 19° 19° 21° 18° 23° 18–23°
1d · 2026-07-29 21° 23° 19° 19° 23° 18° 22° 18–23°
0d · 2026-07-30 21° 23° 19° 18° 22° 17° 23° 17–23°
actual 18°

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.