Was the forecast right for Phoenix on Thu Sep 24?
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 Thu Sep 24 high anywhere from 31° to 39°;by the final call, the day before, the field had settled to a median of 35°. The day verified at 31° against the PHX observations — thunderstorms.
AIFS landed closest, off by 0.2°. GEM ran 5° warm.
What every model said, at every lead
Daily-high calls for Thu Sep 24 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 · 2026-09-09 | — | 35° | — | — | 39° | — | — | 35–39° |
| 14d · 2026-09-10 | 31° | 37° | 31° | — | 39° | — | — | 31–39° |
| 13d · 2026-09-11 | 32° | 35° | 37° | — | 33° | — | — | 32–37° |
| 12d · 2026-09-12 | 35° | 36° | 37° | — | 32° | — | — | 32–37° |
| 11d · 2026-09-13 | 33° | 36° | 36° | — | 34° | — | — | 33–36° |
| 10d · 2026-09-14 | 33° | 36° | 30° | — | 40° | — | — | 30–40° |
| 9d · 2026-09-15 | 37° | 38° | 36° | 36° | 38° | — | — | 36–38° |
| 8d · 2026-09-16 | 38° | 31° | 38° | 33° | 38° | — | — | 31–38° |
| 7d · 2026-09-17 | 38° | 34° | 40° | 31° | 36° | — | — | 31–40° |
| 6d · 2026-09-18 | 39° | 35° | 39° | 35° | 37° | 37° | 29° | 29–39° |
| 5d · 2026-09-19 | 39° | 36° | 38° | 37° | 36° | 37° | 34° | 34–39° |
| 4d · 2026-09-20 | 38° | 35° | 38° | 38° | 37° | 30° | 35° | 30–38° |
| 3d · 2026-09-21 | 35° | 34° | 37° | 37° | 36° | 35° | 38° | 34–38° |
| 2d · 2026-09-22 | 36° | 34° | 35° | 37° | 37° | 34° | 36° | 34–37° |
| 1d · 2026-09-23 | 31° | 34° | 33° | 36° | 35° | 36° | 35° | 31–36° |
| actual | 31° |
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.