The Spread

Was the forecast right for London on Sat Aug 15?

London, England · daily high temperature in °F · forecasts from each model's archived runs, verified against the ECMWF IFS analysis

4 days out, 7 models put London's Sat Aug 15 high anywhere from 73° to 82°; by the final call the field had settled to a median of 81°. The ECMWF IFS analysis says the day verified at 80° with 0.01 in of precipitation — drizzle.

ICON landed closest, off by 1.0°. GEM ran 6° hot.

4 days out the models said 73–82; it hit 80. ICON led (off 1.0°F); GEM ran 6°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 Sat Aug 15 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 London scoreboard shows them, labelled.

Lead AIFSAIGFSECMWFGEMGFSICONUKMO Range
4d · 2026-08-11 75° 75° 80° 80° 82° 80° 73° 73–82°
3d · 2026-08-12 77° 77° 78° 84° 80° 81° 76° 76–84°
2d · 2026-08-13 77° 78° 79° 84° 78° 80° 78° 77–84°
1d · 2026-08-14 77° 78° 82° 86° 83° 81° 78° 77–86°
0d · 2026-08-15 78° 79° 81° 86° 82° 81° 81° 78–86°
actual 80°

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 London — 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.