Frost dates for 98029 — Issaquah, WA
Last spring frostMar 30median date
First fall frostNov 7median date
Growing season222 daysfrost-free
Hardiness zone8bZone 8b
How Issaquah compares
- In 8 years out of 10, the last spring frost in Issaquah falls between March 4 and April 21, a 48-day window. The first fall frost falls between October 22 and December 1.
- The median last frost is 22 days earlier than the Washington median of Apr 21.
- Its 222-day growing season is longer than 76% of the 491 Washington places with a regular frost season (state median 182 days).
- The last frost is 14 days later than the zone 8b median of Mar 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 8b chart.
- The weather station records an average of 54 nights a year at or below 32°F.
- Issaquah shares its weather station with Sammamish, WA, 6 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 4 |
| 50% (median) | March 30 |
| 10% (safe for tender plants) | April 21 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 22 |
| 50% (median) | November 7 |
| 90% (late) | December 1 |
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 Issaquah, WA
Frost dates for 98029 — Issaquah, WA — last frost Mar 30, first frost Nov 7, zone 8b. whenisthelastfrost.com
Crop
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Start indoors: Jan 5 to Jan 19Transplant outside: Mar 2 to Mar 16
Start indoors: Jan 19 to Feb 2Transplant outside: Apr 13 to Apr 27
Start indoors: Jan 19 to Feb 2Transplant outside: Apr 13 to Apr 27
Start indoors: Feb 2 to Feb 16Transplant outside: Apr 6 to Apr 20
Start indoors: Feb 2 to Feb 16Transplant outside: Mar 9 to Mar 23Sow outdoors: Mar 2 to Apr 6Plant for fall: Sep 12 to Oct 10
Start indoors: Feb 2 to Feb 16Transplant outside: Mar 2 to Mar 16Sow outdoors: Mar 2 to Mar 16Plant for fall: Aug 29 to Sep 19
Start indoors: Feb 2 to Feb 16Transplant outside: Mar 16 to Mar 30Plant for fall: Aug 1 to Aug 22
Start indoors: Feb 2 to Feb 16Transplant outside: Mar 9 to Mar 23Plant for fall: Aug 1 to Aug 22
Start indoors: Feb 2 to Feb 16Transplant outside: Mar 16 to Mar 30Plant for fall: Aug 1 to Aug 22
Start indoors: Feb 16 to Mar 2Transplant outside: Apr 20 to May 4Sow outdoors: Apr 20 to May 4
Start indoors: Feb 16 to Mar 2Transplant outside: Apr 6 to Apr 20
Sow outdoors: Feb 16 to Mar 9Plant for fall: Aug 15 to Sep 5
Sow outdoors: Feb 16 to Mar 9Plant for fall: Sep 12 to Oct 3
Sow outdoors: Feb 23 to Apr 6Plant for fall: Sep 26 to Oct 17
Start indoors: Mar 2 to Mar 9Transplant outside: Apr 13 to Apr 20Sow outdoors: Apr 6 to Apr 20Plant for fall: Aug 22 to Sep 5
Start indoors: Mar 2 to Mar 9Sow outdoors: Apr 6 to Apr 20Plant for fall: Aug 29 to Sep 12
Start indoors: Mar 2 to Mar 9Sow outdoors: Apr 6 to Apr 20
Start indoors: Mar 2 to Mar 9Transplant outside: Apr 13 to Apr 27
Sow outdoors: Mar 9 to Apr 6Plant for fall: Aug 15 to Aug 29
Sow outdoors: Mar 9 to Apr 6Plant for fall: Aug 29 to Sep 12
Sow outdoors: Mar 9 to Mar 30
Sow outdoors: Mar 16 to Apr 13Plant for fall: Aug 29 to Sep 12
Sow outdoors: Mar 16 to Apr 6Plant for fall: Sep 12 to Oct 3
Sow outdoors: Apr 6 to Apr 27Plant for fall: Aug 22 to Sep 5
Sow outdoors: Apr 6 to Apr 20
Transplant outside: Apr 13 to May 4
Plant for fall: Oct 24 to Nov 28
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Issaquah, WA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 5 – Jan 19 | Mar 2 – Mar 16 | — | — |
| Peppers | Jan 19 – Feb 2 | Apr 13 – Apr 27 | — | — |
| Eggplant | Jan 19 – Feb 2 | Apr 13 – Apr 27 | — | — |
| Tomatoes | Feb 2 – Feb 16 | Apr 6 – Apr 20 | — | — |
| Lettuce | Feb 2 – Feb 16 | Mar 9 – Mar 23 | Mar 2 – Apr 6 | Sep 12 – Oct 10 |
| Kale | Feb 2 – Feb 16 | Mar 2 – Mar 16 | Mar 2 – Mar 16 | Aug 29 – Sep 19 |
| Broccoli | Feb 2 – Feb 16 | Mar 16 – Mar 30 | — | Aug 1 – Aug 22 |
| Cabbage | Feb 2 – Feb 16 | Mar 9 – Mar 23 | — | Aug 1 – Aug 22 |
| Cauliflower | Feb 2 – Feb 16 | Mar 16 – Mar 30 | — | Aug 1 – Aug 22 |
| Okra | Feb 16 – Mar 2 | Apr 20 – May 4 | Apr 20 – May 4 | — |
| Basil | Feb 16 – Mar 2 | Apr 6 – Apr 20 | — | — |
| Peas | — | — | Feb 16 – Mar 9 | Aug 15 – Sep 5 |
| Spinach | — | — | Feb 16 – Mar 9 | Sep 12 – Oct 3 |
| Radishes | — | — | Feb 23 – Apr 6 | Sep 26 – Oct 17 |
| Cucumbers | Mar 2 – Mar 9 | Apr 13 – Apr 20 | Apr 6 – Apr 20 | Aug 22 – Sep 5 |
| Zucchini & Summer Squash | Mar 2 – Mar 9 | — | Apr 6 – Apr 20 | Aug 29 – Sep 12 |
| Winter Squash & Pumpkins | Mar 2 – Mar 9 | — | Apr 6 – Apr 20 | — |
| Melons & Watermelon | Mar 2 – Mar 9 | Apr 13 – Apr 27 | — | — |
| Carrots | — | — | Mar 9 – Apr 6 | Aug 15 – Aug 29 |
| Beets | — | — | Mar 9 – Apr 6 | Aug 29 – Sep 12 |
| Potatoes | — | — | Mar 9 – Mar 30 | — |
| Swiss Chard | — | — | Mar 16 – Apr 13 | Aug 29 – Sep 12 |
| Cilantro | — | — | Mar 16 – Apr 6 | Sep 12 – Oct 3 |
| Green Beans | — | — | Apr 6 – Apr 27 | Aug 22 – Sep 5 |
| Sweet Corn | — | — | Apr 6 – Apr 20 | — |
| Sweet Potatoes | — | Apr 13 – May 4 | — | — |
| Garlic | — | — | — | Oct 24 – Nov 28 |
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 Snoqualmie Falls, WA weather station, 13 km away (elevation 440 ft (134 m)).
ZIP codes in Issaquah: 98027 98029
Frost dates near Issaquah
- Sammamish Mar 30 · Nov 7
- Preston Mar 30 · Nov 7
- Fall City Mar 30 · Nov 7
- Carnation Mar 30 · Nov 7
- Bellevue Mar 8 · Nov 23
- Redmond Mar 8 · Nov 23
- Snoqualmie Mar 30 · Nov 7
- Renton Mar 13 · Nov 16
Frequently asked questions
When is the last frost in Issaquah, WA?
The median last spring frost in Issaquah, WA is March 30. There is still about a 10% chance of frost after April 21, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Issaquah, WA?
The median first fall frost is November 7, with about a 10% chance of frost before October 22.
How long is the growing season in Issaquah, WA?
About 222 days between the median last spring frost and first fall frost.
What planting zone is Issaquah, WA?
Issaquah, WA is in USDA hardiness zone 8b.