Was the forecast right for Philadelphia on Mon Sep 14?
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 14 high anywhere from 75° to 92°; by the final call the field had settled to a median of 76°. The day verified at 78° against the PHL observations — drizzle.
AIFS landed closest, off by 0.2°. ECMWF ran 3° cold.
What every model said, at every lead
Daily-high calls for Mon Sep 14 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 · 2026-08-30 | — | 78° | — | — | 78° | — | — | 78–78° |
| 14d · 2026-08-31 | 86° | 80° | — | — | 82° | — | — | 80–86° |
| 13d · 2026-09-01 | 79° | 79° | 92° | — | 75° | — | — | 75–92° |
| 12d · 2026-09-02 | 90° | 77° | 84° | — | 92° | — | — | 77–92° |
| 11d · 2026-09-03 | 84° | 90° | 71° | — | 90° | — | — | 71–90° |
| 10d · 2026-09-04 | 83° | 86° | 84° | — | 83° | — | — | 83–86° |
| 9d · 2026-09-05 | 75° | 89° | 79° | — | 92° | — | — | 75–92° |
| 8d · 2026-09-06 | 80° | 87° | 94° | 79° | 94° | — | — | 79–94° |
| 7d · 2026-09-07 | 83° | 88° | 83° | 86° | 89° | — | — | 83–89° |
| 6d · 2026-09-08 | 77° | 74° | 84° | 71° | 87° | 79° | — | 71–87° |
| 5d · 2026-09-09 | 76° | 77° | 89° | 79° | 89° | 90° | 86° | 76–90° |
| 4d · 2026-09-10 | 77° | 78° | 78° | 73° | 85° | 77° | 79° | 73–85° |
| 3d · 2026-09-11 | 78° | 78° | 79° | 75° | 76° | 76° | 83° | 75–83° |
| 2d · 2026-09-12 | 78° | 76° | 77° | 74° | 78° | 75° | 80° | 74–80° |
| 1d · 2026-09-13 | 78° | 76° | 76° | 76° | 77° | 76° | 80° | 76–80° |
| 0d · 2026-09-14 | 78° | 76° | 75° | 76° | 78° | 76° | 79° | 75–79° |
| actual | 78° |
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.