Was the forecast right for London on Wed Sep 23?
London, England · daily high temperature in °C · forecasts from each model's archived runs, verified against the EGLL observations
14 days out, 4 models put London's Wed Sep 23 high anywhere from 16° to 25°;by the final call, the day before, the field had settled to a median of 23°. The day verified at 25° against the EGLL observations — cloudy.
GFS landed closest, off by 1.0°. AIGFS ran 3° cool.
What every model said, at every lead
Daily-high calls for Wed Sep 23 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 |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-09-08 | — | 19° | — | — | 17° | — | — | 17–19° |
| 14d · 2026-09-09 | 22° | 25° | 16° | — | 20° | — | — | 16–25° |
| 13d · 2026-09-10 | 21° | 19° | 23° | — | 17° | — | — | 17–23° |
| 12d · 2026-09-11 | 21° | 18° | 16° | — | 22° | — | — | 16–22° |
| 11d · 2026-09-12 | 17° | 17° | 18° | — | 24° | — | — | 17–24° |
| 10d · 2026-09-13 | 19° | 16° | 21° | — | 18° | — | — | 16–21° |
| 9d · 2026-09-14 | 19° | 18° | 25° | 21° | 27° | — | — | 18–27° |
| 8d · 2026-09-15 | 21° | 18° | 24° | 20° | 23° | — | — | 18–24° |
| 7d · 2026-09-16 | 21° | 22° | 21° | 21° | 23° | — | — | 21–23° |
| 6d · 2026-09-17 | 21° | 20° | 20° | 23° | 22° | 23° | 19° | 19–23° |
| 5d · 2026-09-18 | 21° | 20° | 25° | 22° | 24° | 19° | 20° | 19–25° |
| 4d · 2026-09-19 | 20° | 22° | 19° | 22° | 24° | 23° | 20° | 19–24° |
| 3d · 2026-09-20 | 22° | 22° | 22° | 22° | 24° | 23° | 22° | 22–24° |
| 2d · 2026-09-21 | 23° | 21° | 23° | 22° | 23° | 22° | 20° | 20–23° |
| 1d · 2026-09-22 | 23° | 22° | 24° | 23° | 24° | 23° | 22° | 22–24° |
| 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 EGLL observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.