Frost dates for 98027 — Issaquah, WA
Last spring frostApr 20median date
First fall frostOct 25median date
Growing season188 daysfrost-free
Hardiness zone8bZone 8b
How Issaquah compares
- In 8 years out of 10, the last spring frost in Issaquah falls between March 31 and May 10, a 40-day window. The first fall frost falls between October 5 and November 12.
- The median last frost is 1 day earlier than the Washington median of Apr 21.
- Its 188-day growing season is longer than 52% of the 491 Washington places with a regular frost season (state median 182 days).
- The last frost is 35 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 70 nights a year at or below 32°F.
- Compared with Renton, WA, 12 km away, the last frost here is 38 days later than there and the growing season is 60 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 31 |
| 50% (median) | April 20 |
| 10% (safe for tender plants) | May 10 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 5 |
| 50% (median) | October 25 |
| 90% (late) | November 12 |
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 98027 — Issaquah, WA — last frost Apr 20, first frost Oct 25, zone 8b. whenisthelastfrost.com
Crop
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Start indoors: Jan 26 to Feb 9Transplant outside: Mar 23 to Apr 6
Start indoors: Feb 9 to Feb 23Transplant outside: May 4 to May 18
Start indoors: Feb 9 to Feb 23Transplant outside: May 4 to May 18
Start indoors: Feb 23 to Mar 9Transplant outside: Apr 27 to May 11
Start indoors: Feb 23 to Mar 9Transplant outside: Mar 30 to Apr 13Sow outdoors: Mar 23 to Apr 27Plant for fall: Aug 30 to Sep 27
Start indoors: Feb 23 to Mar 9Transplant outside: Mar 23 to Apr 6Sow outdoors: Mar 23 to Apr 6Plant for fall: Aug 16 to Sep 6
Start indoors: Feb 23 to Mar 9Transplant outside: Apr 6 to Apr 20Plant for fall: Jul 19 to Aug 9
Start indoors: Feb 23 to Mar 9Transplant outside: Mar 30 to Apr 13Plant for fall: Jul 19 to Aug 9
Start indoors: Feb 23 to Mar 9Transplant outside: Apr 6 to Apr 20Plant for fall: Jul 19 to Aug 9
Start indoors: Mar 9 to Mar 23Transplant outside: May 11 to May 25Sow outdoors: May 11 to May 25
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 27 to May 11
Sow outdoors: Mar 9 to Mar 30Plant for fall: Aug 2 to Aug 23
Sow outdoors: Mar 9 to Mar 30Plant for fall: Aug 30 to Sep 20
Sow outdoors: Mar 16 to Apr 27Plant for fall: Sep 13 to Oct 4
Start indoors: Mar 23 to Mar 30Transplant outside: May 4 to May 11Sow outdoors: Apr 27 to May 11Plant for fall: Aug 9 to Aug 23
Start indoors: Mar 23 to Mar 30Sow outdoors: Apr 27 to May 11Plant for fall: Aug 16 to Aug 30
Start indoors: Mar 23 to Mar 30Sow outdoors: Apr 27 to May 11
Start indoors: Mar 23 to Mar 30Transplant outside: May 4 to May 18
Sow outdoors: Mar 30 to Apr 27Plant for fall: Aug 2 to Aug 16
Sow outdoors: Mar 30 to Apr 27Plant for fall: Aug 16 to Aug 30
Sow outdoors: Mar 30 to Apr 20
Sow outdoors: Apr 6 to May 4Plant for fall: Aug 16 to Aug 30
Sow outdoors: Apr 6 to Apr 27Plant for fall: Aug 30 to Sep 20
Sow outdoors: Apr 27 to May 18Plant for fall: Aug 9 to Aug 23
Sow outdoors: Apr 27 to May 11
Transplant outside: May 4 to May 25
Plant for fall: Oct 11 to Nov 15
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 26 – Feb 9 | Mar 23 – Apr 6 | — | — |
| Peppers | Feb 9 – Feb 23 | May 4 – May 18 | — | — |
| Eggplant | Feb 9 – Feb 23 | May 4 – May 18 | — | — |
| Tomatoes | Feb 23 – Mar 9 | Apr 27 – May 11 | — | — |
| Lettuce | Feb 23 – Mar 9 | Mar 30 – Apr 13 | Mar 23 – Apr 27 | Aug 30 – Sep 27 |
| Kale | Feb 23 – Mar 9 | Mar 23 – Apr 6 | Mar 23 – Apr 6 | Aug 16 – Sep 6 |
| Broccoli | Feb 23 – Mar 9 | Apr 6 – Apr 20 | — | Jul 19 – Aug 9 |
| Cabbage | Feb 23 – Mar 9 | Mar 30 – Apr 13 | — | Jul 19 – Aug 9 |
| Cauliflower | Feb 23 – Mar 9 | Apr 6 – Apr 20 | — | Jul 19 – Aug 9 |
| Okra | Mar 9 – Mar 23 | May 11 – May 25 | May 11 – May 25 | — |
| Basil | Mar 9 – Mar 23 | Apr 27 – May 11 | — | — |
| Peas | — | — | Mar 9 – Mar 30 | Aug 2 – Aug 23 |
| Spinach | — | — | Mar 9 – Mar 30 | Aug 30 – Sep 20 |
| Radishes | — | — | Mar 16 – Apr 27 | Sep 13 – Oct 4 |
| Cucumbers | Mar 23 – Mar 30 | May 4 – May 11 | Apr 27 – May 11 | Aug 9 – Aug 23 |
| Zucchini & Summer Squash | Mar 23 – Mar 30 | — | Apr 27 – May 11 | Aug 16 – Aug 30 |
| Winter Squash & Pumpkins | Mar 23 – Mar 30 | — | Apr 27 – May 11 | — |
| Melons & Watermelon | Mar 23 – Mar 30 | May 4 – May 18 | — | — |
| Carrots | — | — | Mar 30 – Apr 27 | Aug 2 – Aug 16 |
| Beets | — | — | Mar 30 – Apr 27 | Aug 16 – Aug 30 |
| Potatoes | — | — | Mar 30 – Apr 20 | — |
| Swiss Chard | — | — | Apr 6 – May 4 | Aug 16 – Aug 30 |
| Cilantro | — | — | Apr 6 – Apr 27 | Aug 30 – Sep 20 |
| Green Beans | — | — | Apr 27 – May 18 | Aug 9 – Aug 23 |
| Sweet Corn | — | — | Apr 27 – May 11 | — |
| Sweet Potatoes | — | May 4 – May 25 | — | — |
| Garlic | — | — | — | Oct 11 – Nov 15 |
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 Landsburg, WA weather station, 14 km away (elevation 535 ft (163 m)).
ZIP codes in Issaquah: 98027 98029
Frost dates near Issaquah
- Preston Mar 30 · Nov 7
- Hobart Apr 20 · Oct 25
- Fall City Mar 30 · Nov 7
- Renton Mar 13 · Nov 16
- Sammamish Mar 30 · Nov 7
- Maple Valley Apr 20 · Oct 25
- Snoqualmie Mar 30 · Nov 7
- Bellevue Mar 8 · Nov 23
Frequently asked questions
When is the last frost in Issaquah, WA?
The median last spring frost in Issaquah, WA is April 20. There is still about a 10% chance of frost after May 10, 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 October 25, with about a 10% chance of frost before October 5.
How long is the growing season in Issaquah, WA?
About 188 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.