Was the forecast right for Phoenix on Thu Aug 27?
Phoenix, Arizona · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHX observations
8 days out, 5 models put Phoenix's Thu Aug 27 high anywhere from 104° to 117°;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 — cloudy.
ECMWF landed closest, off by 0.2°. GEM ran 4° cool.
What every model said, at every lead
Daily-high calls for Thu Aug 27 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 · 2026-08-19 | 111° | 104° | 117° | 110° | 107° | — | — | 104–117° |
| 7d · 2026-08-20 | 111° | 107° | 113° | 111° | 113° | — | — | 107–113° |
| 6d · 2026-08-21 | 113° | 108° | 112° | 110° | 110° | 110° | 114° | 108–114° |
| 5d · 2026-08-22 | 113° | 110° | 116° | 111° | 112° | 114° | 115° | 110–116° |
| 4d · 2026-08-23 | 113° | 110° | 115° | 111° | 110° | 113° | 114° | 110–115° |
| 3d · 2026-08-24 | 113° | 110° | 117° | 109° | 112° | 114° | 114° | 109–117° |
| 2d · 2026-08-25 | 113° | 110° | 116° | 109° | 111° | 112° | 114° | 109–116° |
| 1d · 2026-08-26 | 112° | 110° | 113° | 109° | 110° | 111° | 111° | 109–113° |
| 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.