Was the forecast right for Philadelphia on Sat Sep 12?
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 Sat Sep 12 high anywhere from 61° to 88°; by the final call the field had settled to a median of 82°. The day verified at 83° against the PHL observations — drizzle.
UKMO landed closest, off by 0.1°. GFS ran 3° hot.
What every model said, at every lead
Daily-high calls for Sat Sep 12 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 |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-28 | — | 82° | — | — | 79° | — | — | 79–82° |
| 14d · 2026-08-29 | 89° | 81° | — | — | 83° | — | — | 81–89° |
| 13d · 2026-08-30 | 80° | 88° | 70° | — | 61° | — | — | 61–88° |
| 12d · 2026-08-31 | 94° | 84° | 85° | — | 85° | — | — | 84–94° |
| 11d · 2026-09-01 | 95° | 85° | 87° | — | 85° | — | — | 85–95° |
| 10d · 2026-09-02 | 80° | 92° | 79° | — | 83° | — | — | 79–92° |
| 9d · 2026-09-03 | 73° | 80° | 72° | — | 78° | — | — | 72–80° |
| 8d · 2026-09-04 | 70° | 85° | 76° | 72° | 74° | — | — | 70–85° |
| 7d · 2026-09-05 | 87° | 76° | 78° | 84° | 80° | — | — | 76–87° |
| 6d · 2026-09-06 | 83° | 82° | 80° | 77° | 87° | 82° | — | 77–87° |
| 5d · 2026-09-07 | 82° | 82° | 83° | 82° | 82° | 82° | 82° | 82–83° |
| 4d · 2026-09-08 | 75° | 77° | 81° | 81° | 83° | 79° | 84° | 75–84° |
| 3d · 2026-09-09 | 81° | 82° | 82° | 81° | 82° | 81° | 83° | 81–83° |
| 2d · 2026-09-10 | 81° | 82° | 81° | 85° | 87° | 83° | 84° | 81–87° |
| 1d · 2026-09-11 | 82° | 82° | 82° | 82° | 86° | 79° | 84° | 79–86° |
| 0d · 2026-09-12 | 81° | 82° | 84° | 82° | 86° | 81° | 83° | 81–86° |
| actual | 83° |
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.