Was the forecast right for Phoenix on Mon Aug 17?
Phoenix, Arizona · daily high temperature in °F · 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 100° to 107°; by the final call the field had settled to a median of 111°. The ECMWF IFS analysis says the day verified at 114° — partly cloudy.
GFS landed closest, off by 0.3°. GEM ran 4° 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 | — | 104° | — | — | 111° | — | — | 104–111° |
| 14d · 2026-08-03 | 98° | 100° | — | — | 107° | — | — | 98–107° |
| 13d · 2026-08-04 | 103° | 100° | 100° | — | 107° | — | — | 100–107° |
| 12d · 2026-08-05 | 100° | 104° | 108° | — | 105° | — | — | 100–108° |
| 11d · 2026-08-06 | 108° | 100° | 101° | — | 107° | — | — | 100–108° |
| 10d · 2026-08-07 | 107° | 109° | 109° | — | 103° | — | — | 103–109° |
| 9d · 2026-08-08 | 111° | 106° | 112° | — | 104° | — | — | 104–112° |
| 8d · 2026-08-09 | 111° | 105° | 110° | 106° | 106° | — | — | 105–111° |
| 7d · 2026-08-10 | 108° | 105° | 109° | 108° | 106° | — | — | 105–109° |
| 6d · 2026-08-11 | 110° | 106° | 110° | 107° | 106° | 109° | — | 106–110° |
| 5d · 2026-08-12 | 111° | 106° | 110° | 108° | 108° | 112° | 108° | 106–112° |
| 4d · 2026-08-13 | 112° | 108° | 113° | 109° | 109° | 111° | 110° | 108–113° |
| 3d · 2026-08-14 | 113° | 108° | 112° | 109° | 108° | 112° | 108° | 108–113° |
| 2d · 2026-08-15 | 113° | 109° | 112° | 108° | 109° | 111° | 109° | 108–113° |
| 1d · 2026-08-16 | 112° | 110° | 112° | 108° | 114° | 112° | 109° | 108–114° |
| 0d · 2026-08-17 | 112° | 110° | 111° | 110° | 113° | 111° | 110° | 110–113° |
| actual | 114° |
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.