Was the forecast right for Phoenix on Tue Aug 4?
Phoenix, Arizona · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
8 days out, 5 models put Phoenix's Tue Aug 4 high anywhere from 36° to 44°; by the final call the field had settled to a median of 43°. The day verified at 42° against the ECMWF IFS analysis — cloudy.
AIFS landed closest, off by 0.1°. GEM ran 2° 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 | 40° | 42° | 44° | 36° | 43° | — | — | 36–44° |
| 7d · 2026-07-28 | 40° | 41° | 41° | 42° | 43° | — | — | 40–43° |
| 6d · 2026-07-29 | 41° | 42° | 43° | 41° | 42° | 40° | — | 40–43° |
| 5d · 2026-07-30 | 43° | 43° | 42° | 43° | 43° | 45° | 42° | 42–45° |
| 4d · 2026-07-31 | 42° | 43° | 43° | 44° | 44° | 44° | 45° | 42–45° |
| 3d · 2026-08-01 | 42° | 42° | 42° | 44° | 43° | 43° | 43° | 42–44° |
| 2d · 2026-08-02 | 42° | 42° | 43° | 43° | 43° | 43° | 46° | 42–46° |
| 1d · 2026-08-03 | 42° | 42° | 43° | 44° | 43° | 42° | 45° | 42–45° |
| 0d · 2026-08-04 | 42° | 42° | 44° | 44° | 43° | 42° | 43° | 42–44° |
| actual | 42° |
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 ECMWF IFS analysis (temperature_2m_max). Archive depth varies by city; receipts exist only for dates the archive watched arrive.