Was the forecast right for Phoenix on Wed Sep 9?
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 9 high anywhere from 34° to 42°; by the final call the field had settled to a median of 41°. The day verified at 42° against the PHX observations — cloudy.
GEM landed closest, off by 0.3°. AIGFS ran 2° cold.
What every model said, at every lead
Daily-high calls for Wed Sep 9 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 · 2026-08-25 | — | 34° | — | — | 35° | — | — | 34–35° |
| 14d · 2026-08-26 | 40° | 37° | — | — | 38° | — | — | 37–40° |
| 13d · 2026-08-27 | 42° | 39° | 34° | — | 39° | — | — | 34–42° |
| 12d · 2026-08-28 | 45° | 41° | 34° | — | 44° | — | — | 34–45° |
| 11d · 2026-08-29 | 42° | 40° | 39° | — | 41° | — | — | 39–42° |
| 10d · 2026-08-30 | 33° | 40° | 38° | — | 44° | — | — | 33–44° |
| 9d · 2026-08-31 | 40° | 41° | 42° | — | 37° | — | — | 37–42° |
| 8d · 2026-09-01 | 34° | 33° | 29° | 32° | 37° | — | — | 29–37° |
| 7d · 2026-09-02 | 33° | 30° | 43° | 28° | 39° | — | — | 28–43° |
| 6d · 2026-09-03 | 40° | 36° | 41° | 30° | 40° | 43° | — | 30–43° |
| 5d · 2026-09-04 | 41° | 39° | 40° | 38° | 41° | 38° | 36° | 36–41° |
| 4d · 2026-09-05 | 42° | 40° | 39° | 40° | 41° | 41° | 39° | 39–42° |
| 3d · 2026-09-06 | 42° | 40° | 41° | 41° | 41° | 40° | 40° | 40–42° |
| 2d · 2026-09-07 | 41° | 38° | 42° | 41° | 41° | 41° | 43° | 38–43° |
| 1d · 2026-09-08 | 41° | 38° | 41° | 40° | 40° | 41° | 40° | 38–41° |
| 0d · 2026-09-09 | 40° | 39° | 41° | 41° | 40° | 41° | 41° | 39–41° |
| actual | 42° |
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.