The Spread

Was the forecast right for London on Sun Aug 16?

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

5 days out, 7 models put London's Sun Aug 16 high anywhere from 24° to 27°; by the final call the field had settled to a median of 25°. The ECMWF IFS analysis says the day verified at 25° with 1.0 mm of precipitation — drizzle.

AIFS landed closest, off by 0.1°. ECMWF ran 2° cold.

5 days out the models said 24–27; it hit 25. AIFS led (off 0.1°C); ECMWF ran 2°C cold.
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 Sun Aug 16 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
5d · 2026-08-11 24° 24° 25° 25° 27° 25° 25° 24–27°
4d · 2026-08-12 25° 22° 25° 25° 23° 26° 24° 22–26°
3d · 2026-08-13 25° 23° 26° 25° 27° 26° 24° 23–27°
2d · 2026-08-14 26° 24° 27° 25° 25° 25° 24° 24–27°
1d · 2026-08-15 26° 24° 27° 26° 28° 26° 26° 24–28°
0d · 2026-08-16 25° 23° 22° 26° 24° 26° 27° 22–27°
actual 25°

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.