Where the weather models disagree in Boston
Boston, Logan station · daily high temperature in °F · the next 14 days · using data from 2026-09-03T12:50 UTC
The models are furthest apart on Mon Sep 14, where 4 of them put Boston's high anywhere from 65° to 93° — ECMWF coldest, AIGFS hottest. That spread is much greater than average for forecasts with a 11-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 | 76° to 82° | 6° | 4° | AIFS 76° | ECMWF 82° | 79° to 83° |
| Fri Sep 4 | 7 | 79° to 84° | 5° | 6° | GFS 79° | ICON 84° | 82° to 84° |
| Sat Sep 5 | 7 | 69° to 74° | 5° | 4° | GFS 69° | UKMO 74° | 71° to 75° |
| Sun Sep 6 | 7 | 66° to 72° | 6° | 6° | ECMWF 66° | ICON 72° | 66° to 72° |
| Mon Sep 7 | 7 | 73° to 80° | 7° | 7° | UKMO 73° | ICON 80° | 74° to 81° |
| Tue Sep 8 | 7 | 67° to 84° | 17° | 8° | GFS 67° | ICON 84° | 70° to 83° |
| Wed Sep 9 | 6 | 69° to 88° | 19° | 9° | AIFS 69° | ICON 88° | 72° to 88° |
| Thu Sep 10 | 5 | 79° to 91° | 12° | 11° | AIFS 79° | AIGFS 91° | 72° to 90° |
| Fri Sep 11 | 5 | 69° to 76° | 7° | 10° | AIFS 69° | ECMWF 76° | 69° to 86° |
| Sat Sep 12 | 4 | 64° to 74° | 10° | 13° | ECMWF 64° | GFS 74° | 69° to 89° |
| Sun Sep 13 | 4 | 69° to 82° | 13° | 12° | AIFS 69° | AIGFS 82° | 70° to 84° |
| Mon Sep 14 | 4 | 65° to 93° | 28° | 10° | ECMWF 65° | AIGFS 93° | 68° to 87° |
| Tue Sep 15 | 4 | 76° to 92° | 16° | 12° | AIFS 76° | AIGFS 92° | 66° to 88° |
| Wed Sep 16 | 4 | 66° to 78° | 12° | 14° | ECMWF 66° | GFS 78° | 67° to 87° |
Other locations
Atlanta, Georgia Berlin, State of Berlin Buffalo, New York Charlotte, North Carolina Chicago, Illinois Dallas, Texas Denver, Colorado Detroit, Michigan Houston, Texas London, England Los Angeles, California Miami, Florida Milan, Lombardy Minneapolis, Minnesota New Orleans, Louisiana New York, New York Oklahoma City, Oklahoma Orlando, Florida Paris, Île-de-France Region Philadelphia, Pennsylvania Phoenix, Arizona Salt Lake City, Utah San Antonio, Texas San Diego, California San Francisco, California Seattle, Washington St. Louis, Missouri Tampa, Florida Washington, District of Columbia
The Spread — the forecast spread — is in closed beta. These location pages are public while the rest is gated.