Was the forecast right for Phoenix on Fri Sep 4?
Phoenix, Arizona · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHX observations
14 days out, 4 models put Phoenix's Fri Sep 4 high anywhere from 101° to 105°;by the final call, the day before, the field had settled to a median of 100°. The day verified at 104° against the PHX observations — drizzle.
GFS landed closest, off by 1.4°. ICON ran 8° cool.
What every model said, at every lead
Daily-high calls for Fri Sep 4 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 · 2026-08-20 | — | 98° | — | — | 92° | — | — | 92–98° |
| 14d · 2026-08-21 | 103° | 102° | 105° | — | 101° | — | — | 101–105° |
| 13d · 2026-08-22 | 95° | 106° | 107° | — | 107° | — | — | 95–107° |
| 12d · 2026-08-23 | 101° | 103° | 103° | — | 106° | — | — | 101–106° |
| 11d · 2026-08-24 | 103° | 87° | 103° | — | 103° | — | — | 87–103° |
| 10d · 2026-08-25 | 105° | 104° | 100° | — | 101° | — | — | 100–105° |
| 9d · 2026-08-26 | 102° | 101° | 106° | 102° | 102° | — | — | 101–106° |
| 8d · 2026-08-27 | 103° | 102° | 111° | 106° | 104° | — | — | 102–111° |
| 7d · 2026-08-28 | 104° | 104° | 104° | 105° | 101° | — | — | 101–105° |
| 6d · 2026-08-29 | 103° | 106° | 89° | 102° | 101° | 91° | 102° | 89–106° |
| 5d · 2026-08-30 | 102° | 98° | 100° | 101° | 96° | 92° | 99° | 92–102° |
| 4d · 2026-08-31 | 100° | 99° | 101° | 101° | 101° | 96° | 102° | 96–102° |
| 3d · 2026-09-01 | 102° | 99° | 101° | 97° | 102° | 100° | 102° | 97–102° |
| 2d · 2026-09-02 | 102° | 99° | 102° | 98° | 102° | 98° | 102° | 98–102° |
| 1d · 2026-09-03 | 101° | 99° | 102° | 98° | 103° | 96° | 100° | 96–103° |
| 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. 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.