Was the forecast right for Phoenix on Sun Sep 6?
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 Sun Sep 6 high anywhere from 94° to 104°;by the final call, the day before, the field had settled to a median of 103°. The day verified at 107° against the PHX observations — cloudy.
ECMWF landed closest, off by 1.5°. GEM ran 6° cool.
What every model said, at every lead
Daily-high calls for Sun Sep 6 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 · 2026-08-22 | — | 95° | — | — | 105° | — | — | 95–105° |
| 14d · 2026-08-23 | 100° | 100° | 94° | — | 104° | — | — | 94–104° |
| 13d · 2026-08-24 | 102° | 95° | 99° | — | 105° | — | — | 95–105° |
| 12d · 2026-08-25 | 107° | 106° | 103° | — | 101° | — | — | 101–107° |
| 11d · 2026-08-26 | 105° | 101° | 103° | — | 105° | — | — | 101–105° |
| 10d · 2026-08-27 | 104° | 100° | 107° | — | 100° | — | — | 100–107° |
| 9d · 2026-08-28 | 102° | 106° | 110° | 102° | 96° | — | — | 96–110° |
| 8d · 2026-08-29 | 107° | 107° | 94° | 104° | 106° | — | — | 94–107° |
| 7d · 2026-08-30 | 106° | 105° | 101° | 103° | 97° | — | — | 97–106° |
| 6d · 2026-08-31 | 105° | 103° | 108° | 103° | 95° | 101° | 104° | 95–108° |
| 5d · 2026-09-01 | 105° | 103° | 105° | 102° | 101° | 102° | 102° | 101–105° |
| 4d · 2026-09-02 | 104° | 99° | 106° | 100° | 100° | 101° | 103° | 99–106° |
| 3d · 2026-09-03 | 103° | 100° | 105° | 102° | 103° | 100° | 104° | 100–105° |
| 2d · 2026-09-04 | 104° | 102° | 106° | 100° | 102° | 102° | 105° | 100–106° |
| 1d · 2026-09-05 | 103° | 102° | 106° | 101° | 104° | 102° | 103° | 101–106° |
| actual | 107° |
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.