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Was the forecast right for Phoenix on Sun Sep 20?

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 Sun Sep 20 high anywhere from 31° to 41°; by the final call the field had settled to a median of 37°. The day verified at 40° against the PHX observations — cloudy.

ECMWF landed closest, off by 2.1°. AIGFS ran 4° cool.

13 days out the models said 31–41; it hit 40. ECMWF led (off 2.1°C); AIGFS 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 Sun Sep 20 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 · 2026-09-05 — 36° — — 41° — — 36–41°
14d · 2026-09-06 36° 39° — — 39° — — 36–39°
13d · 2026-09-07 36° 31° 38° — 41° — — 31–41°
12d · 2026-09-08 37° 36° 37° — 38° — — 36–38°
11d · 2026-09-09 38° 39° 39° — 40° — — 38–40°
10d · 2026-09-10 38° 40° 32° — 38° — — 32–40°
9d · 2026-09-11 38° 38° 36° — 38° — — 36–38°
8d · 2026-09-12 37° 37° 40° 40° 40° — — 37–40°
7d · 2026-09-13 37° 38° 36° 38° 39° — — 36–39°
6d · 2026-09-14 36° 36° 36° 35° 38° 39° — 35–39°
5d · 2026-09-15 36° 36° 38° 36° 38° 39° 37° 36–39°
4d · 2026-09-16 36° 36° 38° 37° 38° 38° 37° 36–38°
3d · 2026-09-17 36° 36° 35° 37° 37° 38° 36° 35–38°
2d · 2026-09-18 38° 36° 38° 37° 38° 38° 36° 36–38°
1d · 2026-09-19 38° 36° 38° 37° 37° 37° 36° 36–38°
0d · 2026-09-20 38° 36° 38° 37° 37° 37° 37° 36–38°
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.