Was the forecast right for London on Mon Aug 17?
London, England · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
6 days out, 7 models put London's Mon Aug 17 high anywhere from 19° to 24°; by the final call the field had settled to a median of 26°. The ECMWF IFS analysis says the day verified at 26° — cloudy.
GFS landed closest, off by 0.1°.
What every model said, at every lead
Daily-high calls for Mon Aug 17 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 | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 6d · 2026-08-11 | 21° | 22° | 22° | 19° | 22° | 24° | 22° | 19–24° |
| 5d · 2026-08-12 | 23° | 22° | 25° | 24° | 24° | 29° | 24° | 22–29° |
| 4d · 2026-08-13 | 25° | 24° | 25° | 26° | 27° | 23° | 27° | 23–27° |
| 3d · 2026-08-14 | 26° | 24° | 28° | 26° | 28° | 23° | 26° | 23–28° |
| 2d · 2026-08-15 | 25° | 23° | 27° | 29° | 27° | 24° | 26° | 23–29° |
| 1d · 2026-08-16 | 24° | 23° | 26° | 26° | 28° | 26° | 26° | 23–28° |
| 0d · 2026-08-17 | 25° | 25° | 25° | 27° | 26° | 26° | 26° | 25–27° |
| actual | 26° |
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.