Was the forecast right for Phoenix on Sat Aug 29?
Phoenix, Arizona · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHX observations
10 days out, 4 models put Phoenix's Sat Aug 29 high anywhere from 108° to 114°;by the final call, the day before, the field had settled to a median of 108°. The day verified at 113° against the PHX observations — drizzle.
ECMWF landed closest, off by 1.9°. AIFS ran 7° cool.
What every model said, at every lead
Daily-high calls for Sat Aug 29 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 |
|---|---|---|---|---|---|---|---|---|
| 10d · 2026-08-19 | 112° | 108° | 114° | — | 111° | — | — | 108–114° |
| 9d · 2026-08-20 | 111° | 107° | 114° | — | 113° | — | — | 107–114° |
| 8d · 2026-08-21 | 108° | 106° | 116° | 110° | 112° | — | — | 106–116° |
| 7d · 2026-08-22 | 106° | 107° | 113° | 112° | 111° | — | — | 106–113° |
| 6d · 2026-08-23 | 104° | 105° | 109° | 109° | 109° | 104° | 96° | 96–109° |
| 5d · 2026-08-24 | 104° | 102° | 109° | 107° | 102° | 104° | 107° | 102–109° |
| 4d · 2026-08-25 | 104° | 103° | 107° | 109° | 105° | 110° | 109° | 103–110° |
| 3d · 2026-08-26 | 106° | 106° | 108° | 104° | 106° | 110° | 107° | 104–110° |
| 2d · 2026-08-27 | 105° | 104° | 110° | 109° | 105° | 109° | 109° | 104–110° |
| 1d · 2026-08-28 | 106° | 107° | 111° | 109° | 108° | 110° | 108° | 106–111° |
| actual | 113° |
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.