Where the weather models disagree in Seattle
Seattle, Sea-Tac station · daily high temperature in °F · the next 14 days · using data from 2026-09-03T19:50 UTC
The models are furthest apart on Tue Sep 15, where 4 of them put Seattle's high anywhere from 63° to 83° — ECMWF coldest, AIGFS hottest. That spread is greater than average for forecasts with a 12-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 °F · 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 | 61° to 67° | 6° | 7° | GEM 61° | GFS 67° | 66° to 71° |
| Fri Sep 4 | 7 | 66° to 71° | 5° | 6° | AIFS 66° | UKMO 71° | 69° to 74° |
| Sat Sep 5 | 7 | 65° to 70° | 5° | 8° | AIFS 65° | UKMO 70° | 67° to 76° |
| Sun Sep 6 | 7 | 68° to 74° | 6° | 8° | ICON 68° | GFS 74° | 72° to 77° |
| Mon Sep 7 | 7 | 65° to 79° | 14° | 10° | AIFS 65° | GFS 79° | 68° to 80° |
| Tue Sep 8 | 7 | 67° to 74° | 7° | 11° | GEM 67° | GFS 74° | 68° to 78° |
| Wed Sep 9 | 7 | 67° to 78° | 11° | 10° | ICON 67° | GFS 78° | 67° to 81° |
| Thu Sep 10 | 5 | 64° to 76° | 12° | 12° | AIGFS 64° | GFS 76° | 61° to 84° |
| Fri Sep 11 | 5 | 61° to 69° | 8° | 13° | AIGFS 61° | ECMWF 69° | 63° to 79° |
| Sat Sep 12 | 5 | 65° to 77° | 12° | 11° | GEM 65° | ECMWF 77° | 63° to 75° |
| Sun Sep 13 | 4 | 68° to 76° | 8° | 14° | AIFS 68° | ECMWF 76° | 60° to 74° |
| Mon Sep 14 | 4 | 63° to 79° | 16° | 11° | ECMWF 63° | AIGFS 79° | 63° to 79° |
| Tue Sep 15 | 4 | 63° to 83° | 20° | 12° | ECMWF 63° | AIGFS 83° | 62° to 78° |
| Wed Sep 16 | 4 | 66° to 72° | 6° | 18° | AIFS 66° | GFS 72° | 64° to 78° |
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