Was the forecast right for Philadelphia on Mon Aug 31?
Philadelphia, Pennsylvania · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHL observations
6 days out, 6 models put Philadelphia's Mon Aug 31 high anywhere from 87° to 93°; by the final call the field had settled to a median of 84°. The day verified at 82° against the PHL observations — cloudy.
GEM landed closest, off by 0.0°. ECMWF ran 6° hot.
What every model said, at every lead
Daily-high calls for Mon Aug 31 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 Philadelphia scoreboard shows them, labelled.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 6d · 2026-08-25 | 91° | 91° | 88° | 87° | 93° | 91° | — | 87–93° |
| 5d · 2026-08-26 | 85° | 91° | 93° | 89° | 79° | 92° | 91° | 79–93° |
| 4d · 2026-08-27 | 86° | 90° | 91° | 87° | 90° | 89° | 89° | 86–91° |
| 3d · 2026-08-28 | 86° | 86° | 87° | 87° | 86° | 82° | 89° | 82–89° |
| 2d · 2026-08-29 | 85° | 86° | 86° | 80° | 85° | 82° | 88° | 80–88° |
| 1d · 2026-08-30 | 85° | 83° | 89° | 83° | 84° | 85° | 87° | 83–89° |
| 0d · 2026-08-31 | 84° | 80° | 88° | 82° | 84° | 79° | 84° | 79–88° |
| actual | 82° |
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 Philadelphia — 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 PHL observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.