Was the forecast right for Phoenix on Wed Sep 30?
Phoenix, Arizona · daily high temperature in °C · forecasts from each model's archived runs, verified against the PHX observations
14 days out, 4 models put Phoenix's Wed Sep 30 high anywhere from 37° to 39°;by the final call, the day before, the field had settled to a median of 28°. The day verified at 30° against the PHX observations — drizzle.
GFS landed closest, off by 0.2°. GEM ran 7° cool.
What every model said, at every lead
Daily-high calls for Wed Sep 30 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 · 2026-09-15 | — | 39° | — | — | 39° | — | — | 39–39° |
| 14d · 2026-09-16 | 38° | 37° | 39° | — | 38° | — | — | 37–39° |
| 13d · 2026-09-17 | 38° | 33° | 37° | — | 41° | — | — | 33–41° |
| 12d · 2026-09-18 | 35° | 36° | 38° | — | 37° | — | — | 35–38° |
| 11d · 2026-09-19 | 38° | 38° | 37° | — | 37° | — | — | 37–38° |
| 10d · 2026-09-20 | 26° | 28° | 37° | — | 32° | — | — | 26–37° |
| 9d · 2026-09-21 | 37° | 34° | 37° | 36° | 40° | — | — | 34–40° |
| 8d · 2026-09-22 | 37° | 35° | 37° | 34° | 32° | — | — | 32–37° |
| 7d · 2026-09-23 | 27° | 24° | 31° | 35° | 29° | — | — | 24–35° |
| 6d · 2026-09-24 | 27° | 28° | 30° | 32° | 33° | 29° | 29° | 27–33° |
| 5d · 2026-09-25 | 29° | 28° | 25° | 33° | 33° | 27° | 33° | 25–33° |
| 4d · 2026-09-26 | 28° | 29° | 28° | 30° | 31° | 32° | 31° | 28–32° |
| 3d · 2026-09-27 | 28° | 29° | 27° | 28° | 31° | 30° | 29° | 27–31° |
| 2d · 2026-09-28 | 28° | 28° | 27° | 22° | 31° | 28° | 30° | 22–31° |
| 1d · 2026-09-29 | 28° | 28° | 26° | 23° | 30° | 26° | 28° | 23–30° |
| actual | 30° |
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. The actual values are the ones in hand when this receipt was settled, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; receipts exist only for dates the archive watched arrive.