Sumas, WA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sumas, a city in Whatcom County, Washington.
Today
56°F
Mostly Cloudy
Mostly cloudy. High near 56, with temperatures falling to around 52 in the afternoon. North northwest wind around 1 mph.
7-day forecast for Sumas
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 56°F | Mostly Cloudy | 1 mph NNW | 6% |
| Tonight | 40°F | Partly Cloudy | 2 mph SSE | 5% |
| Wednesday | 59°F | Mostly Sunny then Slight Chance Light Rain | 2 mph NE | 16% |
| Wednesday Night | 47°F | Light Rain | 1 to 6 mph SE | 98% |
| Thursday | 56°F | Light Rain Likely | 2 to 7 mph S | 57% |
| Thursday Night | 46°F | Light Rain | 2 to 6 mph SE | 93% |
| Friday | 55°F | Light Rain | 5 to 8 mph SSE | 93% |
| Friday Night | 45°F | Chance Light Rain | 3 to 7 mph ESE | 47% |
| Saturday | 59°F | Chance Light Rain | 7 mph E | 47% |
| Saturday Night | 48°F | Light Rain | 7 to 15 mph SSE | 82% |
| Sunday | 55°F | Light Rain | 6 to 12 mph SSW | 82% |
| Sunday Night | 41°F | Chance Light Rain | 6 mph ESE | 38% |
| Monday | 54°F | Light Rain Likely | 5 mph ENE | 56% |
| Monday Night | 45°F | Light Rain | 5 to 8 mph E | 78% |
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 Nov 3, 2026.