Was the forecast right for Phoenix on Fri Sep 11?
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 Fri Sep 11 high anywhere from 87° to 106°; by the final call the field had settled to a median of 104°. The day verified at 106° against the PHX observations — showers.
GEM landed closest, off by 1.2°. AIFS ran 7° cold.
What every model said, at every lead
Daily-high calls for Fri Sep 11 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 · 2026-08-27 | — | 89° | — | — | 103° | — | — | 89–103° |
| 14d · 2026-08-28 | 103° | 102° | — | — | 107° | — | — | 102–107° |
| 13d · 2026-08-29 | 104° | 106° | 87° | — | 103° | — | — | 87–106° |
| 12d · 2026-08-30 | 99° | 102° | 107° | — | 106° | — | — | 99–107° |
| 11d · 2026-08-31 | 99° | 80° | 98° | — | 88° | — | — | 80–99° |
| 10d · 2026-09-01 | 90° | 88° | 84° | — | 100° | — | — | 84–100° |
| 9d · 2026-09-02 | 83° | 91° | 106° | — | 93° | — | — | 83–106° |
| 8d · 2026-09-03 | 102° | 92° | 95° | 88° | 96° | — | — | 88–102° |
| 7d · 2026-09-04 | 102° | 104° | 98° | 91° | 99° | — | — | 91–104° |
| 6d · 2026-09-05 | 102° | 102° | 99° | 106° | 100° | 98° | — | 98–106° |
| 5d · 2026-09-06 | 103° | 103° | 105° | 106° | 106° | 101° | 106° | 101–106° |
| 4d · 2026-09-07 | 96° | 100° | 106° | 106° | 98° | 106° | 104° | 96–106° |
| 3d · 2026-09-08 | 100° | 101° | 103° | 103° | 100° | 102° | 105° | 100–105° |
| 2d · 2026-09-09 | 101° | 102° | 106° | 105° | 104° | 105° | 104° | 101–106° |
| 1d · 2026-09-10 | 101° | 103° | 106° | 105° | 104° | 105° | 105° | 101–106° |
| 0d · 2026-09-11 | 99° | 103° | 104° | 105° | 104° | 104° | 103° | 99–105° |
| actual | 106° |
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.