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Weather in Sumas, WA · National Weather Service + NOAA

Sumas stays cool in summer

Sumas has mild winters and pleasant summers, with plenty of rain. A typical July afternoon reaches 76°, a January night drops to 33°, and about 11 inches of snow falls in a normal winter. In November, a normal day reaches 49° and a normal night drops to 38°.

Winter 45°/34°Spring 59°/42°Summer 74°/53°Fall 60°/44°
Right now
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Sunrise 6:58 am · sunset 4:46 pm

Getting the latest forecast from the National Weather Service…

What stands out about Sumas’s weather

Read from 30 years of NOAA records. Each one opens the full story on the Climate page.

Climate →
Cool summersJuly afternoons average 76°, cooler than 98% of U.S. towns.A wet climate64 inches of rain and melted snow a year, more than 99% of U.S. towns.
A normal year

Where today sits in Sumas’s year

Typical highs and lows month by month, from 30 years of NOAA records.

Full climate →
Winter
45° / 34°
4 days with an inch or more of snow
Spring
59° / 42°
Last frost around Apr 18
Summer
74° / 53°
2 days reach 90° in a normal year
Fall now
60° / 44°
First frost around Oct 18
Pastthe usual first frost (Oct 18). Last frost next spring: Apr 18
Best months to be outside
MayJunJulAugSep
Highs of 62–84° and lows of 40° or more
How much snow does Sumas get?About 11 inches a winter.When is it wettest?November, with 9.9 inches.Is it warmer than it used to be?+1.4° vs. the 20th century.

Weather talk

Road reports, first frosts and storm memories from neighbors in Sumas.

Town Square →
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Forecast, conditions and alerts: National Weather Service. Climate: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000. Temperatures and rainfall come from NOAA’s gridded normals for Sumas itself (about a 3-mile square). Snow, frost dates and day counts: the NOAA station at Clearbrook, WA (3 mi). Sunrise and sunset are calculated from the town’s position. Normals are 30-year averages, not a forecast.