The Spread

Was the forecast right for Phoenix on Wed Sep 2?

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 Wed Sep 2 high anywhere from 41° to 43°; by the final call the field had settled to a median of 38°. The day verified at 40° against the PHX observations — drizzle.

GFS landed closest, off by 0.5°. AIFS ran 3° cold.

13 days out the models said 41–43; it hit 40. GFS led (off 0.5°C); AIFS ran 3°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 Wed Sep 2 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
13d · 2026-08-20 41° 42° 43° — 42° — — 41–43°
12d · 2026-08-21 42° 39° 38° — 35° — — 35–42°
11d · 2026-08-22 43° 41° 45° — 44° — — 41–45°
10d · 2026-08-23 40° 40° 44° — 41° — — 40–44°
9d · 2026-08-24 38° 38° 41° — 41° — — 38–41°
8d · 2026-08-25 38° 37° 40° 38° 42° — — 37–42°
7d · 2026-08-26 39° 39° 40° 39° 40° — — 39–40°
6d · 2026-08-27 39° 39° 41° 41° 38° 41° — 38–41°
5d · 2026-08-28 39° 39° 40° 39° 37° 37° 41° 37–41°
4d · 2026-08-29 37° 38° 40° 39° 39° 37° 40° 37–40°
3d · 2026-08-30 37° 38° 39° 37° 39° 38° 39° 37–39°
2d · 2026-08-31 38° 36° 38° 38° 38° 39° 39° 36–39°
1d · 2026-09-01 37° 37° 38° 38° 39° 37° 37° 37–39°
0d · 2026-09-02 37° 38° 38° 38° 40° 38° 38° 37–40°
actual 40°

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.