Was the forecast right for Philadelphia on Thu Sep 3?
Philadelphia, Pennsylvania · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHL observations
9 days out, 4 models put Philadelphia's Thu Sep 3 high anywhere from 82° to 93°; by the final call the field had settled to a median of 88°. The day verified at 89° against the PHL observations, with 1.34 in of precipitation — thunderstorms.
AIGFS landed closest, off by 1.4°. AIFS ran 5° cold.
What every model said, at every lead
Daily-high calls for Thu Sep 3 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 |
|---|---|---|---|---|---|---|---|---|
| 9d · 2026-08-25 | 87° | 82° | 93° | — | 84° | — | — | 82–93° |
| 8d · 2026-08-26 | 87° | 88° | 99° | 81° | 99° | — | — | 81–99° |
| 7d · 2026-08-27 | 85° | 85° | 81° | 87° | 90° | — | — | 81–90° |
| 6d · 2026-08-28 | 84° | 87° | 97° | 86° | 98° | 87° | — | 84–98° |
| 5d · 2026-08-29 | 92° | 92° | 102° | 90° | 88° | 91° | 94° | 88–102° |
| 4d · 2026-08-30 | 90° | 92° | 94° | 92° | 95° | 94° | 91° | 90–95° |
| 3d · 2026-08-31 | 87° | 90° | 92° | 92° | 91° | 94° | 94° | 87–94° |
| 2d · 2026-09-01 | 84° | 90° | 87° | 87° | 87° | 86° | 93° | 84–93° |
| 1d · 2026-09-02 | 86° | 90° | 88° | 85° | 92° | 87° | 92° | 85–92° |
| 0d · 2026-09-03 | 84° | 88° | 88° | 85° | 93° | 87° | 92° | 84–93° |
| 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.