Frost dates & planting calendar for Seattle, WA
Frost dates
Mar 8
Last spring frost, typical
In half of the years that freeze, the last frost comes later.
Safer date: Mar 29. Only 1 freeze year in 10 has a frost after this.
Nov 23
First fall frost, typical
In half of the years that freeze, it comes earlier.
Early date: Nov 4. Only 1 freeze year in 10 freezes before this.
259
Days, typical frost-free season
From NOAA’s 1991–2020 climate normals for this station.
9a
USDA hardiness zone
Coldest night of the winter, averaged over 1991–2020: 20 to 25°F (−6.7 to −3.9°C).
Zone for ZIP 98121, the ZIP nearest the city center; zones can vary within a city. What zone 9a means.
What to plant right now
As of Nov 9, 2026
Typical frost-free season: 259 days. Station: Seattle Sand Pt Wsfo, WA, 10 km away. Source: NOAA NCEI U.S. Climate Normals 1991–2020 (32°F threshold).
Hardiness zones: 2023 USDA Plant Hardiness Zone Map, PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed 9 Nov 2026.
Can I plant tomatoes now?
Not yet. Start tomato seeds indoors from Feb 1 to Feb 15, then plant them out from Mar 29 to Apr 12.
Planting calendar
Windows are counted from the safer dates (Mar 29 in spring, Nov 4 in fall). Going by the typical dates instead gains you about 3 weeks in spring, with more risk.
February
The next window opens in February.
Tomatotender
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 15
- Transplant outdoors
- Mar 29 – Apr 12
Eggplanttender
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 15
- Transplant outdoors
- Mar 29 – Apr 12
Broccolihardy
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 15
- Transplant outdoors
- Mar 1 – Mar 29
- Sow outdoors
- Mar 1 – Mar 15
- Sow for fall
- Aug 12 – Aug 26
Cabbagehardy
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 15
- Transplant outdoors
- Mar 1 – Mar 29
- Sow outdoors
- Mar 1 – Mar 15
- Sow for fall
- Aug 12 – Aug 26
Cauliflowerhalf hardy
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 15
- Transplant outdoors
- Mar 15 – Mar 29
- Sow outdoors
- Mar 8 – Mar 29
- Sow for fall
- Aug 12 – Aug 26
Brussels sproutshardy
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 15
- Sow outdoors
- Mar 8 – Mar 8
- Sow for fall
- Aug 12 – Aug 26
Marigoldtender
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 1
- Transplant outdoors
- Mar 29 – Mar 29
Calendulahalf hardy
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 15
- Sow outdoors
- Mar 22 – Mar 29
Mexican sunflowertender
Next: start indoors from Feb 1
- Start indoors
- Feb 1 – Feb 15
- Sow outdoors
- Mar 29 – Mar 29
Leaf lettucehardy
Next: sow outdoors from Feb 15
- Transplant outdoors
- Mar 1 – Mar 15
- Sow outdoors
- Feb 15 – Mar 15
Head lettucehardy
Next: sow outdoors from Feb 15
- Transplant outdoors
- Mar 1 – Mar 15
- Sow outdoors
- Feb 15 – Mar 15
Zinniatender
Next: start indoors from Feb 15
- Start indoors
- Feb 15 – Mar 1
- Sow outdoors
- Mar 29 – Mar 29
Nasturtiumtender
Next: start indoors from Feb 15
- Start indoors
- Feb 15 – Mar 1
- Sow outdoors
- Mar 29 – Mar 29
Sunflowertender
Next: start indoors from Feb 15
- Start indoors
- Feb 15 – Mar 1
March
The next window opens in March.
Cucumbertender
Next: start indoors from Mar 1
- Start indoors
- Mar 1 – Mar 15
- Sow outdoors
- Mar 29 – Apr 5
Summer squashtender
Next: start indoors from Mar 1
- Start indoors
- Mar 1 – Mar 15
- Sow outdoors
- Mar 29 – Apr 5
Winter squashtender
Next: start indoors from Mar 1
- Start indoors
- Mar 1 – Mar 15
- Sow outdoors
- Apr 5 – Apr 12
Watermelontender
Next: start indoors from Mar 1
- Start indoors
- Mar 1 – Mar 15
- Transplant outdoors
- Apr 5 – Apr 12
- Sow outdoors
- Apr 5 – Apr 12
Cantaloupetender
Next: start indoors from Mar 1
- Start indoors
- Mar 1 – Mar 8
- Sow outdoors
- Apr 5 – Apr 12
Peahardy
Next: sow outdoors from Mar 1
- Sow outdoors
- Mar 1 – Mar 15
Spinachhardy
Next: sow outdoors from Mar 1
- Sow outdoors
- Mar 1 – Mar 15
Kohlrabihardy
Next: sow outdoors from Mar 1
- Sow outdoors
- Mar 1 – Mar 15
- Sow for fall
- Aug 12 – Aug 26
Radishhardy
Next: sow outdoors from Mar 1
- Sow outdoors
- Mar 1 – Mar 15
Beethalf hardy
Next: sow outdoors from Mar 1
- Sow outdoors
- Mar 1 – Mar 29
Turniphardy
Next: sow outdoors from Mar 1
- Sow outdoors
- Mar 1 – Mar 15
Bulb onionhardy
Next: sow outdoors from Mar 1
- Sow outdoors
- Mar 1 – Mar 15
Green onionhardy
Next: sow outdoors from Mar 1
- Sow outdoors
- Mar 1 – Mar 15
Kalehardy
Next: sow outdoors from Mar 8
- Sow outdoors
- Mar 8 – Mar 8
- Sow for fall
- Aug 12 – Aug 26
Collardshardy
Next: sow outdoors from Mar 8
- Sow outdoors
- Mar 8 – Mar 8
- Sow for fall
- Aug 12 – Aug 26
Swiss chardhalf hardy
Next: sow outdoors from Mar 15
- Sow outdoors
- Mar 15 – Mar 29
Carrothalf hardy
Next: sow outdoors from Mar 15
- Sow outdoors
- Mar 15 – Mar 29
Potatohalf hardy
Next: sow outdoors from Mar 15
- Sow outdoors
- Mar 15 – Mar 29
Parsniphalf hardy
Next: sow outdoors from Mar 15
- Sow outdoors
- Mar 15 – Mar 29
Dillhalf hardy
Next: sow outdoors from Mar 15
- Sow outdoors
- Mar 15 – Mar 22
Bush beantender
Next: sow outdoors from Mar 29
- Sow outdoors
- Mar 29 – Mar 29
Pole beantender
Next: sow outdoors from Mar 29
- Sow outdoors
- Mar 29 – Mar 29
Sweet corntender
Next: sow outdoors from Mar 29
- Sow outdoors
- Mar 29 – Mar 29
Basiltender
Next: sow outdoors from Mar 29
- Sow outdoors
- Mar 29 – Mar 29
Marjoramtender
Next: transplant outdoors from Mar 29
- Transplant outdoors
- Mar 29 – Mar 29
September
The next window opens in September.
Sweet alyssumhardy
Next: sow for fall from Sep 23
- Sow for fall
- Sep 23 – Sep 23
No window listed
No frost-based window for these crops.
Mustard greenshalf hardy
No frost-based window listed.
No frost-based sowing window is listed for mustard greens.
Crop guidance from university extension services; see each crop page for sources.
Questions
- When is the last frost in Seattle?
- The typical last spring frost (32°F) in Seattle is Mar 8. In 1 out of 10 years that freeze, a frost still comes after Mar 29.
- When is the first frost in Seattle?
- The typical first fall frost is Nov 23. In 1 out of 10 years that freeze, it arrives before Nov 4.
- When should I start tomato seeds in Seattle?
- Start tomato seeds indoors between Feb 1 and Feb 15, counting back from the safer last-frost date.
- What planting zone is Seattle in?
- Seattle is in USDA hardiness zone 9a on the 2023 map, going by ZIP 98121, the ZIP nearest the city center. Zones can vary within a city. The zone describes how cold winter nights get, not when to plant; for that, use the frost dates on this page.
Nearby cities
- Portland, OR 233 km
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