Where the weather models disagree in Phoenix
Phoenix, Sky Harbor station · daily high temperature in °C · the next 14 days · using data from 2026-09-03T12:50 UTC
The models are furthest apart on Thu Sep 10, where 5 of them put Phoenix's high anywhere from 26° to 40° — GEM coldest, ECMWF hottest. That spread is much greater than average for forecasts with a 7-day lead at this location.
The band, day by day
The shaded band is the lowest to the highest model high each day; the line is the median model. The band pales as models drop out with lead — 4 to 7 models across these days — so a narrower far end is fewer opinions, not more agreement.
Every day, every model
highs in °C · typical spread is the median for that lead over the last month here
How this page is built
The models are the independent global centres Open-Meteo serves for this point — GFS, ECMWF IFS, ICON, GEM, UKMO and the AIFS and AIGFS AI models — as The Spread recorded them at its last sweep. NBM and every other blend are left out: a consensus product hides the disagreement this page exists to show.
Each model publishes to a different horizon, which is why Models is counted per day rather than once. Beyond day 14 only two models remain and both are NOAA's, so the page stops there. Range is the lowest to the highest model high; Spread is the difference between those two printed numbers.
Typical spread is the median spread for that lead over the last month of forecasts made here, shown only once ten days of them exist. It is there because a wide band ten days out is ordinary and the same band tomorrow is not — so nothing on this page is called a divergence; the comparison is against what this lead usually looks like at this location.
GEFS p10–p90 is one centre's ensemble, shown beside the band and never as it: it verifies a few degrees warm at every lead.
| Day | Models | Range | Spread | Typical spread | Coldest | Hottest | GEFS p10–p90 |
|---|---|---|---|---|---|---|---|
| Thu Sep 3 | 7 | 36° to 39° | 3° | 2° | UKMO 36° | ICON 39° | 36° to 38° |
| Fri Sep 4 | 7 | 36° to 39° | 3° | 3° | ICON 36° | GFS 39° | 37° to 39° |
| Sat Sep 5 | 7 | 34° to 39° | 5° | 3° | UKMO 34° | ECMWF 39° | 37° to 39° |
| Sun Sep 6 | 7 | 38° to 40° | 2° | 3° | ICON 38° | ECMWF 40° | 36° to 39° |
| Mon Sep 7 | 7 | 39° to 42° | 3° | 4° | ICON 39° | ECMWF 42° | 37° to 40° |
| Tue Sep 8 | 7 | 39° to 42° | 3° | 4° | UKMO 39° | ECMWF 42° | 38° to 41° |
| Wed Sep 9 | 6 | 30° to 43° | 13° | 4° | GEM 30° | ICON 43° | 37° to 42° |
| Thu Sep 10 | 5 | 26° to 40° | 14° | 4° | GEM 26° | ECMWF 40° | 34° to 41° |
| Fri Sep 11 | 5 | 31° to 39° | 8° | 5° | GEM 31° | AIFS 39° | 32° to 39° |
| Sat Sep 12 | 4 | 34° to 40° | 6° | 4° | ECMWF 34° | AIFS 40° | 32° to 38° |
| Sun Sep 13 | 4 | 33° to 42° | 9° | 4° | AIGFS 33° | AIFS 42° | 33° to 37° |
| Mon Sep 14 | 4 | 31° to 44° | 13° | 7° | AIGFS 31° | AIFS 44° | 33° to 39° |
| Tue Sep 15 | 4 | 30° to 42° | 12° | 5° | ECMWF 30° | AIFS 42° | 33° to 40° |
| Wed Sep 16 | 4 | 29° to 41° | 12° | 5° | ECMWF 29° | AIFS 41° | 33° to 40° |
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