Was the forecast right for Phoenix on Thu Sep 10?
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 Thu Sep 10 high anywhere from 94° to 104°;by the final call, the day before, the field had settled to a median of 106°. The day verified at 109° against the PHX observations — drizzle.
GFS landed closest, off by 1.9°. AIGFS ran 5° cool.
What every model said, at every lead
Daily-high calls for Thu Sep 10 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, labeled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-26 | — | 100° | — | — | 95° | — | — | 95–100° |
| 14d · 2026-08-27 | 104° | 97° | 96° | — | 94° | — | — | 94–104° |
| 13d · 2026-08-28 | 98° | 100° | 97° | — | 92° | — | — | 92–100° |
| 12d · 2026-08-29 | 99° | 105° | 88° | — | 106° | — | — | 88–106° |
| 11d · 2026-08-30 | 94° | 102° | 97° | — | 109° | — | — | 94–109° |
| 10d · 2026-08-31 | 97° | 90° | 87° | — | 95° | — | — | 87–97° |
| 9d · 2026-09-01 | 88° | 90° | 94° | 88° | 96° | — | — | 88–96° |
| 8d · 2026-09-02 | 87° | 84° | 104° | 82° | 92° | — | — | 82–104° |
| 7d · 2026-09-03 | 102° | 86° | 105° | 79° | 100° | — | — | 79–105° |
| 6d · 2026-09-04 | 106° | 103° | 105° | 105° | 103° | 95° | 108° | 95–108° |
| 5d · 2026-09-05 | 103° | 106° | 103° | 105° | 109° | 104° | 105° | 103–109° |
| 4d · 2026-09-06 | 104° | 104° | 106° | 104° | 106° | 108° | 99° | 99–108° |
| 3d · 2026-09-07 | 106° | 102° | 107° | 104° | 105° | 109° | 107° | 102–109° |
| 2d · 2026-09-08 | 106° | 103° | 107° | 106° | 107° | 108° | 106° | 103–108° |
| 1d · 2026-09-09 | 106° | 104° | 106° | 105° | 107° | 107° | 106° | 104–107° |
| actual | 109° |
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 day was verified, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; verified days exist only for dates the archive watched arrive.