Sumas, WA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sumas, a city in Whatcom County, Washington.
Overnight
55°F
Mostly Clear
Mostly clear, with a low around 55. West wind around 1 mph.
7-day forecast for Sumas
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 55°F | Mostly Clear | 1 mph W | 0% |
| Tuesday | 89°F | Patchy Smoke | 1 to 7 mph WNW | 0% |
| Tuesday Night | 59°F | Patchy Smoke then Mostly Clear | 1 to 6 mph SW | 0% |
| Wednesday | 92°F | Sunny then Patchy Smoke | 1 to 7 mph W | 0% |
| Wednesday Night | 60°F | Mostly Clear | 1 to 7 mph SSW | 0% |
| Thursday | 92°F | Sunny | 1 to 7 mph SW | 0% |
| Thursday Night | 62°F | Mostly Clear | 1 to 7 mph S | 0% |
| Friday | 86°F | Sunny | 1 to 9 mph SW | 0% |
| Friday Night | 60°F | Mostly Clear | 0 to 8 mph SSW | 0% |
| Saturday | 82°F | Sunny | 0 to 9 mph SSW | 0% |
| Saturday Night | 58°F | Mostly Clear | 1 to 9 mph S | 0% |
| Sunday | 78°F | Mostly Sunny | 1 to 8 mph SW | 0% |
| Sunday Night | 56°F | Mostly Clear | 0 to 8 mph S | 3% |
| Monday | 78°F | Mostly Sunny | 0 to 8 mph SW | 3% |
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 Aug 4, 2026.