Was the forecast right for Philadelphia on Sun Sep 27?
Philadelphia, Pennsylvania · daily high temperature in °C · forecasts from each model's archived runs, verified against the PHL observations
14 days out, 4 models put Philadelphia's Sun Sep 27 high anywhere from 20° to 26°;by the final call, the day before, the field had settled to a median of 18°. The day verified at 19° against the PHL observations, with 40.1 mm of precipitation — thunderstorms.
ECMWF landed closest, off by 0.9°. AIGFS ran 4° cool.
What every model said, at every lead
Daily-high calls for Sun Sep 27 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 · 2026-09-12 | — | 20° | — | — | 24° | — | — | 20–24° |
| 14d · 2026-09-13 | 25° | 26° | 23° | — | 20° | — | — | 20–26° |
| 13d · 2026-09-14 | 22° | 26° | 26° | — | 19° | — | — | 19–26° |
| 12d · 2026-09-15 | 23° | 27° | 24° | — | 30° | — | — | 23–30° |
| 11d · 2026-09-16 | 22° | 24° | 20° | — | 21° | — | — | 20–24° |
| 10d · 2026-09-17 | 17° | 21° | 18° | — | 20° | — | — | 17–21° |
| 9d · 2026-09-18 | 17° | 22° | 22° | 16° | 24° | — | — | 16–24° |
| 8d · 2026-09-19 | 26° | 23° | 19° | 16° | 15° | — | — | 15–26° |
| 7d · 2026-09-20 | 20° | 23° | 19° | 21° | 21° | — | — | 19–23° |
| 6d · 2026-09-21 | 17° | 24° | 19° | 23° | 26° | 16° | 22° | 16–26° |
| 5d · 2026-09-22 | 17° | 22° | 22° | 23° | 24° | 18° | 23° | 17–24° |
| 4d · 2026-09-23 | 18° | 23° | 16° | 23° | 17° | 16° | 17° | 16–23° |
| 3d · 2026-09-24 | 17° | 17° | 18° | 17° | 16° | 17° | 19° | 16–19° |
| 2d · 2026-09-25 | 18° | 16° | 18° | 15° | 16° | 18° | 18° | 15–18° |
| 1d · 2026-09-26 | 18° | 16° | 18° | 17° | 17° | 18° | 18° | 16–18° |
| actual | 19° |
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.