Was the forecast right for Phoenix on Wed Sep 16?
Phoenix, Arizona · daily high temperature in °C · forecasts from each model's archived runs, verified against the PHX observations
13 days out, 4 models put Phoenix's Wed Sep 16 high anywhere from 29° to 41°; by the final call the field had settled to a median of 33°. The day verified at 35° against the PHX observations, with 9.1 mm of precipitation — thunderstorms.
GEM landed closest, off by 0.6°. AIGFS ran 3° cold.
What every model said, at every lead
Daily-high calls for Wed Sep 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 Phoenix scoreboard shows them, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-09-01 | — | 36° | — | — | 33° | — | — | 33–36° |
| 14d · 2026-09-02 | 35° | 39° | — | — | 38° | — | — | 35–39° |
| 13d · 2026-09-03 | 41° | 36° | 29° | — | 38° | — | — | 29–41° |
| 12d · 2026-09-04 | 37° | 36° | 34° | — | 33° | — | — | 33–37° |
| 11d · 2026-09-05 | 37° | 38° | 34° | — | 40° | — | — | 34–40° |
| 10d · 2026-09-06 | 31° | 37° | 39° | — | 39° | — | — | 31–39° |
| 9d · 2026-09-07 | 31° | 37° | 33° | — | 36° | — | — | 31–37° |
| 8d · 2026-09-08 | 35° | 36° | 40° | 28° | 37° | — | — | 28–40° |
| 7d · 2026-09-09 | 37° | 37° | 40° | 36° | 36° | — | — | 36–40° |
| 6d · 2026-09-10 | 36° | 37° | 38° | 33° | 38° | 33° | — | 33–38° |
| 5d · 2026-09-11 | 32° | 36° | 34° | 28° | 36° | 36° | 37° | 28–37° |
| 4d · 2026-09-12 | 31° | 36° | 38° | 37° | 37° | 33° | 39° | 31–39° |
| 3d · 2026-09-13 | 32° | 35° | 35° | 36° | 35° | 34° | 39° | 32–39° |
| 2d · 2026-09-14 | 30° | 35° | 32° | 33° | 36° | 34° | 38° | 30–38° |
| 1d · 2026-09-15 | 29° | 30° | 31° | 33° | 35° | 32° | 32° | 29–35° |
| 0d · 2026-09-16 | 33° | 32° | 33° | 34° | 33° | 32° | 32° | 32–34° |
| actual | 35° |
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 Phoenix — 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 PHX observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.