Was the forecast right for Phoenix on Sat Sep 12?
Phoenix, Arizona · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHX observations
13 days out, 4 models put Phoenix's Sat Sep 12 high anywhere from 98° to 108°; by the final call the field had settled to a median of 100°. The day verified at 104° against the PHX observations — thunderstorms.
GEM landed closest, off by 0.8°. ECMWF ran 9° cold.
What every model said, at every lead
Daily-high calls for Sat Sep 12 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 · 2026-08-28 | — | 101° | — | — | 107° | — | — | 101–107° |
| 14d · 2026-08-29 | 105° | 104° | — | — | 99° | — | — | 99–105° |
| 13d · 2026-08-30 | 98° | 102° | 102° | — | 108° | — | — | 98–108° |
| 12d · 2026-08-31 | 94° | 89° | 98° | — | 87° | — | — | 87–98° |
| 11d · 2026-09-01 | 78° | 89° | 85° | — | 94° | — | — | 78–94° |
| 10d · 2026-09-02 | 79° | 89° | 99° | — | 93° | — | — | 79–99° |
| 9d · 2026-09-03 | 104° | 95° | 93° | — | 95° | — | — | 93–104° |
| 8d · 2026-09-04 | 102° | 98° | 94° | 93° | 98° | — | — | 93–102° |
| 7d · 2026-09-05 | 101° | 101° | 91° | 105° | 95° | — | — | 91–105° |
| 6d · 2026-09-06 | 104° | 103° | 97° | 104° | 103° | 102° | — | 97–104° |
| 5d · 2026-09-07 | 101° | 102° | 104° | 107° | 101° | 100° | 104° | 100–107° |
| 4d · 2026-09-08 | 102° | 103° | 101° | 104° | 100° | 97° | 103° | 97–104° |
| 3d · 2026-09-09 | 103° | 102° | 102° | 103° | 103° | 97° | 102° | 97–103° |
| 2d · 2026-09-10 | 102° | 101° | 103° | 104° | 103° | 102° | 103° | 101–104° |
| 1d · 2026-09-11 | 102° | 102° | 103° | 103° | 102° | 96° | 102° | 96–103° |
| 0d · 2026-09-12 | 97° | 102° | 95° | 103° | 102° | 98° | 100° | 95–103° |
| actual | 104° |
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.