Was the forecast right for Philadelphia on Mon Sep 7?
Philadelphia, Pennsylvania · daily high temperature in °F · forecasts from each model's archived runs, verified against the PHL observations
13 days out, 4 models put Philadelphia's Mon Sep 7 high anywhere from 82° to 94°;by the final call, the day before, the field had settled to a median of 80°. The day verified at 82° against the PHL observations — drizzle.
GFS landed closest, off by 0.3°. AIGFS ran 3° cool.
What every model said, at every lead
Daily-high calls for Mon Sep 7 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 |
|---|---|---|---|---|---|---|---|---|
| 13d · 2026-08-25 | 82° | 85° | 85° | — | 94° | — | — | 82–94° |
| 12d · 2026-08-26 | 88° | 81° | 82° | — | 80° | — | — | 80–88° |
| 11d · 2026-08-27 | 84° | 93° | 89° | — | 85° | — | — | 84–93° |
| 10d · 2026-08-28 | 79° | 77° | 88° | — | 81° | — | — | 77–88° |
| 9d · 2026-08-29 | 84° | 80° | 75° | 76° | 83° | — | — | 75–84° |
| 8d · 2026-08-30 | 81° | 79° | 82° | 83° | 79° | — | — | 79–83° |
| 7d · 2026-08-31 | 80° | 80° | 73° | 80° | 80° | — | — | 73–80° |
| 6d · 2026-09-01 | 82° | 79° | 81° | 78° | 82° | 81° | 83° | 78–83° |
| 5d · 2026-09-02 | 82° | 79° | 81° | 79° | 81° | 82° | 82° | 79–82° |
| 4d · 2026-09-03 | 80° | 79° | 78° | 79° | 81° | 81° | 81° | 78–81° |
| 3d · 2026-09-04 | 80° | 80° | 81° | 83° | 82° | 82° | 80° | 80–83° |
| 2d · 2026-09-05 | 80° | 79° | 81° | 81° | 81° | 80° | 80° | 79–81° |
| 1d · 2026-09-06 | 80° | 79° | 81° | 83° | 82° | 80° | 80° | 79–83° |
| 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. 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.