Sumas, WA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sumas, a city in Whatcom County, Washington.
Today
75°F
Partly Sunny
Partly sunny, with a high near 75. West wind 1 to 5 mph.
7-day forecast for Sumas
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 75°F | Partly Sunny | 1 to 5 mph W | 0% |
| Tonight | 51°F | Partly Cloudy | 0 to 3 mph NNW | 0% |
| Sunday | 76°F | Mostly Sunny | 0 to 5 mph WNW | 0% |
| Sunday Night | 52°F | Partly Cloudy | 0 to 5 mph SSW | 0% |
| Monday | 74°F | Mostly Sunny | 0 to 7 mph SSW | 0% |
| Monday Night | 52°F | Partly Cloudy | 0 to 7 mph S | 0% |
| Tuesday | 72°F | Mostly Sunny | 0 to 7 mph S | 0% |
| Tuesday Night | 50°F | Partly Cloudy | 1 to 7 mph S | 13% |
| Wednesday | 70°F | Partly Sunny then Slight Chance Light Rain | 1 to 5 mph SSW | 15% |
| Wednesday Night | 50°F | Slight Chance Light Rain then Mostly Cloudy | 1 to 5 mph SSE | 15% |
| Thursday | 69°F | Partly Sunny then Slight Chance Light Rain | 1 to 6 mph WNW | 15% |
| Thursday Night | 49°F | Chance Light Rain | 1 to 6 mph SSW | 26% |
| Friday | 68°F | Chance Light Rain | 1 to 6 mph ESE | 26% |
| Friday Night | 48°F | Slight Chance Light Rain | 2 to 6 mph SE | 16% |
Forecast source: National Weather Service (api.weather.gov) for Sumas (48.996, -122.268). Updated through the day.
Growing snapshot for Sumas
Last spring frost
Apr 18
First fall frost
Oct 18
Growing season
185 days
Hardiness zone
8a
More local growing data for Sumas: nearby ZIP 98295 weather · frost dates · planting calendar · Washington frost dates
Nearby towns & communities
Acme
Bellingham
Birch Bay
Blaine
Custer
Deming
Everson
Ferndale
Geneva
Glacier
Kendall
Lynden
Maple Falls
Marietta-Alderwood
Nooksack
Peaceful Valley
Point Roberts
Sudden Valley
Climate data from the nearest NOAA station, Clearbrook, Wa (6.2 mi from Sumas). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.