Was the forecast right for Phoenix on Sun Aug 23?
Phoenix, Arizona · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHX observations
4 days out, 7 models put Phoenix's Sun Aug 23 high anywhere from 99° to 111°;by the final call, the day before, the field had settled to a median of 111°. The day verified at 113° against the PHX observations — drizzle.
ICON landed closest, off by 0.4°. GEM ran 11° cool.
What every model said, at every lead
Daily-high calls for Sun Aug 23 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 |
|---|---|---|---|---|---|---|---|---|
| 4d · 2026-08-19 | 104° | 107° | 111° | 99° | 109° | 111° | 108° | 99–111° |
| 3d · 2026-08-20 | 106° | 108° | 112° | 107° | 112° | 114° | 101° | 101–114° |
| 2d · 2026-08-21 | 107° | 108° | 113° | 108° | 112° | 114° | 101° | 101–114° |
| 1d · 2026-08-22 | 108° | 110° | 114° | 102° | 112° | 113° | 111° | 102–114° |
| 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.