Was the forecast right for Phoenix on Tue Aug 4?
Phoenix, Arizona · daily high temperature · forecasts from each model's archived runs, verified against ERA5
8 days out, 5 models put Phoenix's Tue Aug 4 high anywhere from 97° to 111°; by the final call the field had settled to a median of 109°. ERA5 says the day verified at 108° — cloudy.
AIFS landed closest, off by 0.1°. GEM ran 3° hot.
What every model said, at every lead
Daily-high calls for Tue Aug 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 |
|---|---|---|---|---|---|---|---|---|
| 8d · 2026-07-27 | 104° | 108° | 111° | 97° | 109° | — | — | 97–111° |
| 7d · 2026-07-28 | 105° | 106° | 106° | 108° | 110° | — | — | 105–110° |
| 6d · 2026-07-29 | 106° | 108° | 109° | 106° | 108° | 104° | — | 104–109° |
| 5d · 2026-07-30 | 109° | 109° | 108° | 110° | 109° | 113° | 108° | 108–113° |
| 4d · 2026-07-31 | 108° | 109° | 109° | 112° | 111° | 111° | 112° | 108–112° |
| 3d · 2026-08-01 | 108° | 107° | 108° | 112° | 110° | 109° | 110° | 107–112° |
| 2d · 2026-08-02 | 108° | 107° | 110° | 110° | 109° | 109° | 114° | 107–114° |
| 1d · 2026-08-03 | 108° | 107° | 109° | 111° | 109° | 108° | 112° | 107–112° |
| 0d · 2026-08-04 | 108° | 108° | 110° | 111° | 109° | 108° | 110° | 108–111° |
| actual | 108° |
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 ERA5 reanalysis (temperature_2m_max). Archive depth varies by city; receipts exist only for dates the archive watched arrive.