Was the forecast right for Philadelphia on Fri Sep 4?
Philadelphia, Pennsylvania · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHL observations
10 days out, 4 models put Philadelphia's Fri Sep 4 high anywhere from 72° to 100°; by the final call the field had settled to a median of 89°. The day verified at 89° against the PHL observations, with 0.04 in of precipitation — drizzle.
AIGFS landed closest, off by 0.3°. GEM ran 4° cold.
What every model said, at every lead
Daily-high calls for Fri Sep 4 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 |
|---|---|---|---|---|---|---|---|---|
| 10d · 2026-08-25 | 88° | 84° | 100° | — | 72° | — | — | 72–100° |
| 9d · 2026-08-26 | 86° | 85° | 95° | — | 85° | — | — | 85–95° |
| 8d · 2026-08-27 | 85° | 82° | 81° | 82° | 81° | — | — | 81–85° |
| 7d · 2026-08-28 | 84° | 81° | 86° | 84° | 89° | — | — | 81–89° |
| 6d · 2026-08-29 | 82° | 84° | 89° | 82° | 85° | 92° | — | 82–92° |
| 5d · 2026-08-30 | 88° | 87° | 91° | 87° | 88° | 88° | 90° | 87–91° |
| 4d · 2026-08-31 | 88° | 84° | 88° | 84° | 91° | 84° | 90° | 84–91° |
| 3d · 2026-09-01 | 88° | 87° | 86° | 80° | 88° | 83° | 88° | 80–88° |
| 2d · 2026-09-02 | 88° | 87° | 86° | 82° | 87° | 86° | 87° | 82–88° |
| 1d · 2026-09-03 | 87° | 88° | 84° | 84° | 90° | 85° | 90° | 84–90° |
| 0d · 2026-09-04 | 90° | 89° | 90° | 85° | 90° | 88° | 87° | 85–90° |
| actual | 89° |
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.