Frost dates for 98158 — Seattle, WA
How Seattle compares
- In 8 years out of 10, the last spring frost in Seattle falls between February 5 and March 23, a 46-day window. The first fall frost falls between November 6 and December 15.
- The median last frost is 50 days earlier than the Washington median of Apr 21.
- Its 266-day growing season is among the longest of the 491 Washington places with a regular frost season.
- The last frost is typical for zone 9a, where the median is Mar 3.
- 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 5 |
| 50% (median) | March 2 |
| 10% (safe for tender plants) | March 23 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 6 |
| 50% (median) | November 23 |
| 90% (late) | December 15 |
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 98158 — Seattle, WA — last frost Mar 2, 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 8 – Dec 22 | Feb 2 – Feb 16 | — | — |
| Peppers | Dec 22 – Jan 5 | Mar 16 – Mar 30 | — | — |
| Eggplant | Dec 22 – Jan 5 | Mar 16 – Mar 30 | — | — |
| Tomatoes | Jan 5 – Jan 19 | Mar 9 – Mar 23 | — | — |
| Lettuce | Jan 5 – Jan 19 | Feb 9 – Feb 23 | Feb 2 – Mar 9 | Sep 28 – Oct 26 |
| Kale | Jan 5 – Jan 19 | Feb 2 – Feb 16 | Feb 2 – Feb 16 | Sep 14 – Oct 5 |
| Broccoli | Jan 5 – Jan 19 | Feb 16 – Mar 2 | — | Aug 17 – Sep 7 |
| Cabbage | Jan 5 – Jan 19 | Feb 9 – Feb 23 | — | Aug 17 – Sep 7 |
| Cauliflower | Jan 5 – Jan 19 | Feb 16 – Mar 2 | — | Aug 17 – Sep 7 |
| Okra | Jan 19 – Feb 2 | Mar 23 – Apr 6 | Mar 23 – Apr 6 | — |
| Basil | Jan 19 – Feb 2 | Mar 9 – Mar 23 | — | — |
| Peas | — | — | Jan 19 – Feb 9 | Aug 31 – Sep 21 |
| Spinach | — | — | Jan 19 – Feb 9 | Sep 28 – Oct 19 |
| Radishes | — | — | Jan 26 – Mar 9 | Oct 12 – Nov 2 |
| Cucumbers | Feb 2 – Feb 9 | Mar 16 – Mar 23 | Mar 9 – Mar 23 | Sep 7 – Sep 21 |
| Zucchini & Summer Squash | Feb 2 – Feb 9 | — | Mar 9 – Mar 23 | Sep 14 – Sep 28 |
| Winter Squash & Pumpkins | Feb 2 – Feb 9 | — | Mar 9 – Mar 23 | — |
| Melons & Watermelon | Feb 2 – Feb 9 | Mar 16 – Mar 30 | — | — |
| Carrots | — | — | Feb 9 – Mar 9 | Aug 31 – Sep 14 |
| Beets | — | — | Feb 9 – Mar 9 | Sep 14 – Sep 28 |
| Potatoes | — | — | Feb 9 – Mar 2 | — |
| Swiss Chard | — | — | Feb 16 – Mar 16 | Sep 14 – Sep 28 |
| Cilantro | — | — | Feb 16 – Mar 9 | Sep 28 – Oct 19 |
| Green Beans | — | — | Mar 9 – Mar 30 | Sep 7 – Sep 21 |
| Sweet Corn | — | — | Mar 9 – Mar 23 | — |
| Sweet Potatoes | — | Mar 16 – Apr 6 | — | — |
| 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 Tacoma Intl Ap, WA weather station, about 1 km away (elevation 371 ft (113 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
- Seahurst Mar 2 · Nov 23
- Kent Mar 20 · Nov 10
- Renton Mar 13 · Nov 16
- Vashon Mar 2 · Nov 23
- Burton Mar 2 · Nov 23
- Mercer Island Mar 13 · Nov 17
- Federal Way Mar 20 · Nov 10
- Southworth Mar 13 · Nov 17
Frequently asked questions
When is the last frost in Seattle, WA?
The median last spring frost in Seattle, WA is March 2. There is still about a 10% chance of frost after March 23, 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 6.
How long is the growing season in Seattle, WA?
About 266 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.