Frost dates for 98155 — Seattle, WA
How Seattle compares
- In 8 years out of 10, the last spring frost in Seattle falls between February 13 and March 29, a 44-day window. The first fall frost falls between November 4 and December 16.
- The median last frost is 44 days earlier than the Washington median of Apr 21.
- Its 260-day growing season is longer than 96% of the 491 Washington places with a regular frost season (state median 182 days).
- The last frost is 5 days later than the zone 9a median of Mar 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 9a chart.
- The weather station records an average of 25 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | February 13 |
| 50% (median) | March 8 |
| 10% (safe for tender plants) | March 29 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 4 |
| 50% (median) | November 23 |
| 90% (late) | December 16 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Seattle, WA
Frost dates for 98155 — Seattle, WA — last frost Mar 8, first frost Nov 23, zone 9a. whenisthelastfrost.com
When to plant vegetables in Seattle, WA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Dec 14 – Dec 28 | Feb 8 – Feb 22 | — | — |
| Peppers | Dec 28 – Jan 11 | Mar 22 – Apr 5 | — | — |
| Eggplant | Dec 28 – Jan 11 | Mar 22 – Apr 5 | — | — |
| Tomatoes | Jan 11 – Jan 25 | Mar 15 – Mar 29 | — | — |
| Lettuce | Jan 11 – Jan 25 | Feb 15 – Mar 1 | Feb 8 – Mar 15 | Sep 28 – Oct 26 |
| Kale | Jan 11 – Jan 25 | Feb 8 – Feb 22 | Feb 8 – Feb 22 | Sep 14 – Oct 5 |
| Broccoli | Jan 11 – Jan 25 | Feb 22 – Mar 8 | — | Aug 17 – Sep 7 |
| Cabbage | Jan 11 – Jan 25 | Feb 15 – Mar 1 | — | Aug 17 – Sep 7 |
| Cauliflower | Jan 11 – Jan 25 | Feb 22 – Mar 8 | — | Aug 17 – Sep 7 |
| Okra | Jan 25 – Feb 8 | Mar 29 – Apr 12 | Mar 29 – Apr 12 | — |
| Basil | Jan 25 – Feb 8 | Mar 15 – Mar 29 | — | — |
| Peas | — | — | Jan 25 – Feb 15 | Aug 31 – Sep 21 |
| Spinach | — | — | Jan 25 – Feb 15 | Sep 28 – Oct 19 |
| Radishes | — | — | Feb 1 – Mar 15 | Oct 12 – Nov 2 |
| Cucumbers | Feb 8 – Feb 15 | Mar 22 – Mar 29 | Mar 15 – Mar 29 | Sep 7 – Sep 21 |
| Zucchini & Summer Squash | Feb 8 – Feb 15 | — | Mar 15 – Mar 29 | Sep 14 – Sep 28 |
| Winter Squash & Pumpkins | Feb 8 – Feb 15 | — | Mar 15 – Mar 29 | — |
| Melons & Watermelon | Feb 8 – Feb 15 | Mar 22 – Apr 5 | — | — |
| Carrots | — | — | Feb 15 – Mar 15 | Aug 31 – Sep 14 |
| Beets | — | — | Feb 15 – Mar 15 | Sep 14 – Sep 28 |
| Potatoes | — | — | Feb 15 – Mar 8 | — |
| Swiss Chard | — | — | Feb 22 – Mar 22 | Sep 14 – Sep 28 |
| Cilantro | — | — | Feb 22 – Mar 15 | Sep 28 – Oct 19 |
| Green Beans | — | — | Mar 15 – Apr 5 | Sep 7 – Sep 21 |
| Sweet Corn | — | — | Mar 15 – Mar 29 | — |
| Sweet Potatoes | — | Mar 22 – Apr 12 | — | — |
| Garlic | — | — | — | Nov 9 – Dec 14 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Seattle Sand Pt Wsfo, WA weather station, 8 km away (elevation 59 ft (18 m)).
ZIP codes in Seattle: 98101 98102 98103 98104 98105 98106 98107 98108 98109 98111 98112 98113 98114 98115 98116 98117 98118 98119 98121 98122 98124 98125 98126 98127 98129 98131 98133 98134 98136 98138 98139 98141 98144 98145 98146 98148 98154 98155 98158 98160 98161 98164 98165 98166 98168 98170 98174 98175 98177 98178 98181 98185 98188 98190 98191 98194 98195 98198 98199
Frost dates near Seattle
- Kenmore Mar 8 · Nov 23
- Mountlake Terrace Mar 8 · Nov 23
- Bothell Mar 8 · Nov 23
- Edmonds Mar 9 · Nov 17
- Lynnwood Mar 9 · Nov 17
- Kirkland Mar 8 · Nov 23
- Mill Creek Mar 9 · Nov 17
- Medina Mar 8 · Nov 23
Frequently asked questions
When is the last frost in Seattle, WA?
The median last spring frost in Seattle, WA is March 8. There is still about a 10% chance of frost after March 29, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Seattle, WA?
The median first fall frost is November 23, with about a 10% chance of frost before November 4.
How long is the growing season in Seattle, WA?
About 260 days between the median last spring frost and first fall frost.
What planting zone is Seattle, WA?
Seattle, WA is in USDA hardiness zone 9a.