Was the forecast right for Phoenix on Sat Sep 5?
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 5 high anywhere from 97° to 108°; by the final call the field had settled to a median of 101°. The day verified at 104° against the PHX observations — cloudy.
GFS landed closest, off by 1.6°. UKMO ran 5° cold.
What every model said, at every lead
Daily-high calls for Sat Sep 5 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 · 2026-08-21 | — | 98° | — | — | 92° | — | — | 92–98° |
| 14d · 2026-08-22 | 109° | 101° | — | — | 112° | — | — | 101–112° |
| 13d · 2026-08-23 | 98° | 99° | 97° | — | 108° | — | — | 97–108° |
| 12d · 2026-08-24 | 108° | 100° | 103° | — | 99° | — | — | 99–108° |
| 11d · 2026-08-25 | 100° | 98° | 102° | — | 100° | — | — | 98–102° |
| 10d · 2026-08-26 | 100° | 93° | 101° | — | 103° | — | — | 93–103° |
| 9d · 2026-08-27 | 99° | 100° | 99° | — | 102° | — | — | 99–102° |
| 8d · 2026-08-28 | 107° | 99° | 106° | 104° | 102° | — | — | 99–107° |
| 7d · 2026-08-29 | 104° | 106° | 99° | 101° | 100° | — | — | 99–106° |
| 6d · 2026-08-30 | 104° | 104° | 92° | 99° | 99° | 91° | — | 91–104° |
| 5d · 2026-08-31 | 92° | 99° | 88° | 101° | 84° | 90° | 102° | 84–102° |
| 4d · 2026-09-01 | 102° | 99° | 103° | 100° | 97° | 102° | 101° | 97–103° |
| 3d · 2026-09-02 | 102° | 100° | 103° | 100° | 101° | 101° | 99° | 99–103° |
| 2d · 2026-09-03 | 101° | 95° | 102° | 100° | 101° | 98° | 92° | 92–102° |
| 1d · 2026-09-04 | 101° | 98° | 99° | 99° | 102° | 101° | 92° | 92–102° |
| 0d · 2026-09-05 | 101° | 100° | 102° | 101° | 102° | 101° | 99° | 99–102° |
| 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.