Was the forecast right for Phoenix on Sat Aug 29?
Phoenix, Arizona · daily high temperature in °C · 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 42° to 46°;by the final call, the day before, the field had settled to a median of 42°. The day verified at 45° against the PHX observations — drizzle.
ECMWF landed closest, off by 1.1°. AIFS ran 4° 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 | 44° | 42° | 46° | — | 44° | — | — | 42–46° |
| 9d · 2026-08-20 | 44° | 42° | 46° | — | 45° | — | — | 42–46° |
| 8d · 2026-08-21 | 42° | 41° | 47° | 44° | 45° | — | — | 41–47° |
| 7d · 2026-08-22 | 41° | 42° | 45° | 44° | 44° | — | — | 41–45° |
| 6d · 2026-08-23 | 40° | 41° | 43° | 43° | 43° | 40° | 36° | 36–43° |
| 5d · 2026-08-24 | 40° | 39° | 43° | 42° | 39° | 40° | 42° | 39–43° |
| 4d · 2026-08-25 | 40° | 40° | 41° | 43° | 40° | 43° | 43° | 40–43° |
| 3d · 2026-08-26 | 41° | 41° | 42° | 40° | 41° | 43° | 42° | 40–43° |
| 2d · 2026-08-27 | 41° | 40° | 44° | 43° | 41° | 43° | 43° | 40–44° |
| 1d · 2026-08-28 | 41° | 42° | 44° | 43° | 42° | 43° | 42° | 41–44° |
| 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 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.