The Spread

Was the forecast right for Phoenix on Tue Sep 15?

Phoenix, Arizona · daily high temperature in °C · forecasts from each model's archived runs, verified against the PHX observations

13 days out, 4 models put Phoenix's Tue Sep 15 high anywhere from 30° to 39°; by the final call the field had settled to a median of 36°. The day verified at 39° against the PHX observations — drizzle.

GEM landed closest, off by 2.3°. ICON ran 5° cold.

13 days out the models said 30–39; it hit 39. GEM led (off 2.3°C); ICON ran 5°C cold.
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 15 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 Phoenix scoreboard shows them, labelled.

Lead AIFSAIGFSECMWFGEMGFSICONUKMO Range
15d · 2026-08-31 — 37° — — 34° — — 34–37°
14d · 2026-09-01 33° 35° — — 37° — — 33–37°
13d · 2026-09-02 34° 36° 30° — 39° — — 30–39°
12d · 2026-09-03 42° 32° 30° — 37° — — 30–42°
11d · 2026-09-04 36° 34° 32° — 38° — — 32–38°
10d · 2026-09-05 35° 37° 31° — 38° — — 31–38°
9d · 2026-09-06 30° 35° 37° — 38° — — 30–38°
8d · 2026-09-07 32° 38° 30° 39° 35° — — 30–39°
7d · 2026-09-08 36° 37° 38° 36° 38° — — 36–38°
6d · 2026-09-09 37° 36° 38° 33° 36° 33° — 33–38°
5d · 2026-09-10 37° 36° 37° 34° 36° 31° 37° 31–37°
4d · 2026-09-11 33° 35° 38° 37° 34° 32° 39° 32–39°
3d · 2026-09-12 34° 35° 38° 37° 36° 34° 38° 34–38°
2d · 2026-09-13 34° 35° 35° 38° 38° 36° 40° 34–40°
1d · 2026-09-14 36° 35° 37° 38° 38° 34° 38° 34–38°
0d · 2026-09-15 35° 36° 36° 37° 36° 34° 36° 34–37°
actual 39°

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 Phoenix — 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 PHX observations. Archive depth varies by city; receipts exist only for dates the archive watched arrive.