Renton, WA frost dates
Last spring frostMar 13median date
First fall frostNov 16median date
Growing season248 daysfrost-free
Hardiness zone9aZone 9a
How Renton compares
- In 8 years out of 10, the last spring frost in Renton falls between February 19 and March 31, a 40-day window. The first fall frost falls between October 29 and December 9.
- The median last frost is 39 days earlier than the Washington median of Apr 21.
- Its 248-day growing season is longer than 89% of the 491 Washington places with a regular frost season (state median 182 days).
- The last frost is 10 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 30 nights a year at or below 32°F.
- Compared with Kent, WA, 11 km away, the last frost here is 7 days earlier than there and the growing season is 13 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | February 19 |
| 50% (median) | March 13 |
| 10% (safe for tender plants) | March 31 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 29 |
| 50% (median) | November 16 |
| 90% (late) | December 9 |
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 Renton, WA
Renton, WA frost dates — last frost Mar 13, first frost Nov 16, zone 9a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Dec 19 to Jan 2Start indoors: Dec 19 to Jan 2Transplant outside: Feb 13 to Feb 27
Start indoors: Jan 2 to Jan 16Transplant outside: Mar 27 to Apr 10
Start indoors: Jan 2 to Jan 16Transplant outside: Mar 27 to Apr 10
Start indoors: Jan 16 to Jan 30Transplant outside: Mar 20 to Apr 3
Start indoors: Jan 16 to Jan 30Transplant outside: Feb 20 to Mar 6Sow outdoors: Feb 13 to Mar 20Plant for fall: Sep 21 to Oct 19
Start indoors: Jan 16 to Jan 30Transplant outside: Feb 13 to Feb 27Sow outdoors: Feb 13 to Feb 27Plant for fall: Sep 7 to Sep 28
Start indoors: Jan 16 to Jan 30Transplant outside: Feb 27 to Mar 13Plant for fall: Aug 10 to Aug 31
Start indoors: Jan 16 to Jan 30Transplant outside: Feb 20 to Mar 6Plant for fall: Aug 10 to Aug 31
Start indoors: Jan 16 to Jan 30Transplant outside: Feb 27 to Mar 13Plant for fall: Aug 10 to Aug 31
Start indoors: Jan 30 to Feb 13Transplant outside: Apr 3 to Apr 17Sow outdoors: Apr 3 to Apr 17
Start indoors: Jan 30 to Feb 13Transplant outside: Mar 20 to Apr 3
Sow outdoors: Jan 30 to Feb 20Plant for fall: Aug 24 to Sep 14
Sow outdoors: Jan 30 to Feb 20Plant for fall: Sep 21 to Oct 12
Sow outdoors: Feb 6 to Mar 20Plant for fall: Oct 5 to Oct 26
Start indoors: Feb 13 to Feb 20Transplant outside: Mar 27 to Apr 3Sow outdoors: Mar 20 to Apr 3Plant for fall: Aug 31 to Sep 14
Start indoors: Feb 13 to Feb 20Sow outdoors: Mar 20 to Apr 3Plant for fall: Sep 7 to Sep 21
Start indoors: Feb 13 to Feb 20Sow outdoors: Mar 20 to Apr 3
Start indoors: Feb 13 to Feb 20Transplant outside: Mar 27 to Apr 10
Sow outdoors: Feb 20 to Mar 20Plant for fall: Aug 24 to Sep 7
Sow outdoors: Feb 20 to Mar 20Plant for fall: Sep 7 to Sep 21
Sow outdoors: Feb 20 to Mar 13
Sow outdoors: Feb 27 to Mar 27Plant for fall: Sep 7 to Sep 21
Sow outdoors: Feb 27 to Mar 20Plant for fall: Sep 21 to Oct 12
Sow outdoors: Mar 20 to Apr 10Plant for fall: Aug 31 to Sep 14
Sow outdoors: Mar 20 to Apr 3
Transplant outside: Mar 27 to Apr 17
Plant for fall: Nov 2 to Dec 7
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Renton, WA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Dec 19 – Jan 2 | Feb 13 – Feb 27 | — | — |
| Peppers | Jan 2 – Jan 16 | Mar 27 – Apr 10 | — | — |
| Eggplant | Jan 2 – Jan 16 | Mar 27 – Apr 10 | — | — |
| Tomatoes | Jan 16 – Jan 30 | Mar 20 – Apr 3 | — | — |
| Lettuce | Jan 16 – Jan 30 | Feb 20 – Mar 6 | Feb 13 – Mar 20 | Sep 21 – Oct 19 |
| Kale | Jan 16 – Jan 30 | Feb 13 – Feb 27 | Feb 13 – Feb 27 | Sep 7 – Sep 28 |
| Broccoli | Jan 16 – Jan 30 | Feb 27 – Mar 13 | — | Aug 10 – Aug 31 |
| Cabbage | Jan 16 – Jan 30 | Feb 20 – Mar 6 | — | Aug 10 – Aug 31 |
| Cauliflower | Jan 16 – Jan 30 | Feb 27 – Mar 13 | — | Aug 10 – Aug 31 |
| Okra | Jan 30 – Feb 13 | Apr 3 – Apr 17 | Apr 3 – Apr 17 | — |
| Basil | Jan 30 – Feb 13 | Mar 20 – Apr 3 | — | — |
| Peas | — | — | Jan 30 – Feb 20 | Aug 24 – Sep 14 |
| Spinach | — | — | Jan 30 – Feb 20 | Sep 21 – Oct 12 |
| Radishes | — | — | Feb 6 – Mar 20 | Oct 5 – Oct 26 |
| Cucumbers | Feb 13 – Feb 20 | Mar 27 – Apr 3 | Mar 20 – Apr 3 | Aug 31 – Sep 14 |
| Zucchini & Summer Squash | Feb 13 – Feb 20 | — | Mar 20 – Apr 3 | Sep 7 – Sep 21 |
| Winter Squash & Pumpkins | Feb 13 – Feb 20 | — | Mar 20 – Apr 3 | — |
| Melons & Watermelon | Feb 13 – Feb 20 | Mar 27 – Apr 10 | — | — |
| Carrots | — | — | Feb 20 – Mar 20 | Aug 24 – Sep 7 |
| Beets | — | — | Feb 20 – Mar 20 | Sep 7 – Sep 21 |
| Potatoes | — | — | Feb 20 – Mar 13 | — |
| Swiss Chard | — | — | Feb 27 – Mar 27 | Sep 7 – Sep 21 |
| Cilantro | — | — | Feb 27 – Mar 20 | Sep 21 – Oct 12 |
| Green Beans | — | — | Mar 20 – Apr 10 | Aug 31 – Sep 14 |
| Sweet Corn | — | — | Mar 20 – Apr 3 | — |
| Sweet Potatoes | — | Mar 27 – Apr 17 | — | — |
| Garlic | — | — | — | Nov 2 – Dec 7 |
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 Renton Muni Ap, WA weather station, 4 km away (elevation 30 ft (9 m)).
ZIP codes in Renton: 98055 98056 98057 98058 98059
Frost dates near Renton
- Mercer Island Mar 13 · Nov 17
- Kent Mar 20 · Nov 10
- Issaquah Mar 30 · Nov 7
- Maple Valley Apr 20 · Oct 25
- Bellevue Mar 8 · Nov 23
- Seahurst Mar 2 · Nov 23
- Hobart Apr 20 · Oct 25
- Sammamish Mar 30 · Nov 7
- Medina Mar 8 · Nov 23
- Seattle Mar 13 · Nov 17
Frequently asked questions
When is the last frost in Renton, WA?
The median last spring frost in Renton, WA is March 13. There is still about a 10% chance of frost after March 31, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Renton, WA?
The median first fall frost is November 16, with about a 10% chance of frost before October 29.
How long is the growing season in Renton, WA?
About 248 days between the median last spring frost and first fall frost.
What planting zone is Renton, WA?
Renton, WA is in USDA hardiness zone 9a.