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, 5 models put Philadelphia's Thu Sep 3 high anywhere from 82° to 96°;by the final call, the day before, the field had settled to a median of 90°. The day verified at 89° against the PHL observations, with 1.34 in of precipitation — thunderstorms.
ICON landed closest, off by 0.9°. UKMO ran 5° warm.
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 | 86° | 82° | 96° | 90° | 95° | — | — | 82–96° |
| 8d · 2026-08-26 | 82° | 93° | 92° | 83° | 70° | — | — | 70–93° |
| 7d · 2026-08-27 | 84° | 84° | 88° | 83° | 86° | — | — | 83–88° |
| 6d · 2026-08-28 | 88° | 87° | 95° | 90° | 92° | 90° | 91° | 87–95° |
| 5d · 2026-08-29 | 85° | 90° | 89° | 91° | 83° | 98° | 95° | 83–98° |
| 4d · 2026-08-30 | 89° | 90° | 92° | 93° | 93° | 96° | 91° | 89–96° |
| 3d · 2026-08-31 | 85° | 90° | 89° | 86° | 92° | 92° | 94° | 85–94° |
| 2d · 2026-09-01 | 86° | 90° | 89° | 88° | 93° | 91° | 94° | 86–94° |
| 1d · 2026-09-02 | 85° | 90° | 91° | 86° | 91° | 88° | 94° | 85–94° |
| 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. 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.