Was the forecast right for Philadelphia on Sun Aug 30?
Philadelphia, Pennsylvania · daily high temperature in °C · forecasts from each model's archived runs, verified against the PHL observations
5 days out, 7 models put Philadelphia's Sun Aug 30 high anywhere from 30° to 31°;by the final call, the day before, the field had settled to a median of 30°. The day verified at 31° against the PHL observations, with 0.3 mm of precipitation — drizzle.
GEM landed closest, off by 0.0°. UKMO ran 1° cool.
What every model said, at every lead
Daily-high calls for Sun Aug 30 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 |
|---|---|---|---|---|---|---|---|---|
| 5d · 2026-08-25 | 30° | 30° | 31° | 31° | 31° | 30° | 30° | 30–31° |
| 4d · 2026-08-26 | 31° | 30° | 30° | 31° | 31° | 30° | 31° | 30–31° |
| 3d · 2026-08-27 | 30° | 30° | 30° | 30° | 31° | 31° | 30° | 30–31° |
| 2d · 2026-08-28 | 29° | 30° | 28° | 30° | 32° | 31° | 30° | 28–32° |
| 1d · 2026-08-29 | 30° | 30° | 29° | 31° | 31° | 30° | 29° | 29–31° |
| actual | 31° |
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.