Was the forecast right for Philadelphia on Tue Sep 1?

Philadelphia, Pennsylvania · daily high temperature in °C · forecasts from each model's archived runs, verified against the PHL observations

7 days out, 5 models put Philadelphia's Tue Sep 1 high anywhere from 33° to 36°;by the final call, the day before, the field had settled to a median of 33°. The day verified at 34° against the PHL observations, with 21.1 mm of precipitation — thunderstorms.

UKMO landed closest, off by 0.0°. AIFS ran 4° cool.

7 days out the models said 33–36; it hit 34. UKMO led (off 0.0°C); AIFS ran 4°C cool. — The shareable card for this receipt — what this page looks like pasted into a thread.

What every model said, at every lead

Daily-high calls for Tue Sep 1 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
7d · 2026-08-25	36°	34°	36°	34°	33°	—	—	33–36°
6d · 2026-08-26	32°	32°	34°	32°	33°	34°	34°	32–34°
5d · 2026-08-27	30°	33°	32°	31°	34°	32°	32°	30–34°
4d · 2026-08-28	30°	31°	31°	33°	30°	30°	29°	29–33°
3d · 2026-08-29	30°	32°	35°	35°	34°	34°	33°	30–35°
2d · 2026-08-30	32°	32°	34°	34°	33°	34°	33°	32–34°
1d · 2026-08-31	30°	33°	33°	32°	34°	32°	34°	30–34°
actual								34°

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.