The Spread

Was the forecast right for London on Sun Aug 16?

London, England · daily high temperature in °F · 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 75° to 80°; by the final call the field had settled to a median of 76°. The ECMWF IFS analysis says the day verified at 76° with 0.04 in of precipitation — drizzle.

AIFS landed closest, off by 0.1°. ECMWF ran 4° cold.

5 days out the models said 75–80; it hit 76. AIFS led (off 0.1°F); ECMWF ran 4°F 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 75° 75° 77° 77° 80° 78° 77° 75–80°
4d · 2026-08-12 76° 72° 78° 77° 73° 79° 75° 72–79°
3d · 2026-08-13 76° 73° 79° 77° 81° 79° 76° 73–81°
2d · 2026-08-14 79° 75° 81° 77° 77° 77° 76° 75–81°
1d · 2026-08-15 78° 76° 80° 78° 83° 78° 78° 76–83°
0d · 2026-08-16 76° 74° 72° 78° 75° 79° 80° 72–80°
actual 76°

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.