9 USDA Planting Zones in Northwest Washington, WA: Bellingham to Mount Vernon

Northwest Washington contains nine USDA hardiness zones from zone 5a to 9a, where winter temperatures range from -20°F to 25°F (-28.9°C to -3.9°C). These nine zones are declared by USDA in their latest update of 2023.

The coldest zone in Northwest Washington is USDA zone 5a (-20°F to -15°F / -28.9°C to -26.1°C), found in the higher elevations of Whatcom County. The warmest zone is USDA zone 9a (20°F to 25°F / -6.7°C to -3.9°C), which includes Friday Harbor and portions of Anacortes, Birch Bay, and Point Roberts.

Most cities in the region, including Bellingham, Burlington, Mount Vernon, and Oak Harbor, fall within USDA zones 8a (10°F to 15°F / -12.2°C to -9.4°C) and 8b (15°F to 20°F / -9.4°C to -6.7°C).

Several locations span multiple USDA zones, including Anacortes (8a-8b-9a), Arlington (8a-8b), and Granite Falls (8a-8b). So verify your USDA planting zone of Washington‘s Northwest region, using the interactive map or the USDA hardiness zones table provided below.

USDA Zones Map of Northwest Washington

Select or type your Northwest Washington region location in selection box below, to find its USDA Growing zone.

Planting Zones Table of Northwest Washington

The 29 USDA hardiness zone locations in Northwest Washington are Anacortes, Arlington, Bellingham, Birch Bay, Blaine, Burlington, Coupeville, Custer, Darrington, Everson, Ferndale, Freeland, Friday Harbor, Gold Bar, Granite Falls, Lake Cavanaugh, Lake Stevens, Monroe, Mount Vernon, North Marysville, Oak Harbor, Point Roberts, Sedro Woolley, Silvana, Skagit County, Sultan, Warm Beach, Whatcom County, and Whidbey Island Station. The 29 USDA hardiness zone locations in Northwest Washington are listed below.