Seattle, Washington: freeze dates & growing season

Three different things get called “Seattle” here, so this page is explicit about all three: the metro label (Seattle), the anchor geography (Census ZCTA 98104, a downtown ZIP-code area), and the climate record (the NOAA station below). Windows are calculated from the station — not from your street address.

Climate basis: NOAA station Seattle Boeing Fld, WA (USW00024234), 5 mi (8 km) from the ZCTA 98104 centroid, elevation 20 ft, on the 1991–2020 climate normals.

Last spring freezeMarch 131-in-10 after Apr 1

First fall freezeNovember 171-in-10 before Nov 1

Frost-free season≈ 247 daysmedian at 32°F

Hard freeze, 28°Feb 18 – Dec 2kills even hardy greens

USDA zone9a20 to 25°F winter low — not frost timing

The year

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to Apr 1

The Seattle year: hatched areas are the freeze-likely seasons in 1991–2020 normals.

What that means in practice

Tomatoes: plant March 20 – April 3
Peas: plant January 30 – February 13
Garlic: plant cloves November 24 – December 1

All 79 crops in Seattle

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

Check a specific ZIP instead

Metro climates vary — elevation, water, and urban heat shift freeze dates by days to weeks. Look up your exact ZIP:

Nearby reviewed metros

Portland, OR · Spokane, WA · Boise, ID · Reno, NV · Sacramento, CA