Was the forecast right for London on Thu Sep 17?
London, England · daily high temperature in °F · forecasts from each model's archived runs, verified against the EGLL observations
14 days out, 4 models put London's Thu Sep 17 high anywhere from 59° to 80°; by the final call the field had settled to a median of 68°. The day verified at 70° against the EGLL observations, with 0.04 in of precipitation — drizzle.
UKMO landed closest, off by 0.9°. GEM ran 4° cold.
What every model said, at every lead
Daily-high calls for Thu Sep 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 |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-09-02 | — | 58° | — | — | 78° | — | — | 58–78° |
| 14d · 2026-09-03 | 64° | 59° | 69° | — | 80° | — | — | 59–80° |
| 13d · 2026-09-04 | 62° | 65° | 60° | — | 72° | — | — | 60–72° |
| 12d · 2026-09-05 | 66° | 69° | 61° | — | 74° | — | — | 61–74° |
| 11d · 2026-09-06 | 63° | 74° | 74° | — | 65° | — | — | 63–74° |
| 10d · 2026-09-07 | 62° | 65° | 65° | — | 70° | — | — | 62–70° |
| 9d · 2026-09-08 | 63° | 62° | 65° | 57° | 67° | — | — | 57–67° |
| 8d · 2026-09-09 | 65° | 63° | 67° | 66° | 66° | — | — | 63–67° |
| 7d · 2026-09-10 | 65° | 63° | 63° | 67° | 68° | — | — | 63–68° |
| 6d · 2026-09-11 | 67° | 62° | 69° | 68° | 70° | 65° | 66° | 62–70° |
| 5d · 2026-09-12 | 66° | 64° | 69° | 67° | 65° | 69° | 67° | 64–69° |
| 4d · 2026-09-13 | 64° | 64° | 68° | 65° | 65° | 69° | 66° | 64–69° |
| 3d · 2026-09-14 | 66° | 62° | 68° | 69° | 63° | 67° | 68° | 62–69° |
| 2d · 2026-09-15 | 67° | 65° | 69° | 68° | 69° | 67° | 66° | 65–69° |
| 1d · 2026-09-16 | 68° | 65° | 68° | 67° | 68° | 69° | 68° | 65–69° |
| 0d · 2026-09-17 | 68° | 66° | 69° | 66° | 68° | 68° | 69° | 66–69° |
| actual | 70° |
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.