Was the forecast right for Phoenix on Mon Aug 17?
Phoenix, Arizona · daily high temperature in °C · forecasts from each model's archived runs, verified against the ECMWF IFS analysis
13 days out, 4 models put Phoenix's Mon Aug 17 high anywhere from 38° to 42°; by the final call the field had settled to a median of 44°. The ECMWF IFS analysis says the day verified at 45° — partly cloudy.
GFS landed closest, off by 0.2°. GEM ran 2° cold.
What every model said, at every lead
Daily-high calls for Mon Aug 17 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 · 2026-08-02 | — | 40° | — | — | 44° | — | — | 40–44° |
| 14d · 2026-08-03 | 36° | 38° | — | — | 42° | — | — | 36–42° |
| 13d · 2026-08-04 | 40° | 38° | 38° | — | 42° | — | — | 38–42° |
| 12d · 2026-08-05 | 38° | 40° | 42° | — | 40° | — | — | 38–42° |
| 11d · 2026-08-06 | 42° | 38° | 38° | — | 42° | — | — | 38–42° |
| 10d · 2026-08-07 | 41° | 43° | 43° | — | 39° | — | — | 39–43° |
| 9d · 2026-08-08 | 44° | 41° | 44° | — | 40° | — | — | 40–44° |
| 8d · 2026-08-09 | 44° | 40° | 44° | 41° | 41° | — | — | 40–44° |
| 7d · 2026-08-10 | 42° | 40° | 43° | 42° | 41° | — | — | 40–43° |
| 6d · 2026-08-11 | 44° | 41° | 44° | 42° | 41° | 43° | — | 41–44° |
| 5d · 2026-08-12 | 44° | 41° | 43° | 42° | 42° | 44° | 42° | 41–44° |
| 4d · 2026-08-13 | 44° | 42° | 45° | 43° | 43° | 44° | 43° | 42–45° |
| 3d · 2026-08-14 | 45° | 42° | 44° | 43° | 42° | 44° | 42° | 42–45° |
| 2d · 2026-08-15 | 45° | 43° | 44° | 42° | 43° | 44° | 43° | 42–45° |
| 1d · 2026-08-16 | 45° | 43° | 45° | 42° | 46° | 44° | 43° | 42–46° |
| 0d · 2026-08-17 | 44° | 44° | 44° | 43° | 45° | 44° | 43° | 43–45° |
| actual | 45° |
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.