Frost Dates for Issaquah, WA 98029
Last spring frost April 19 · First fall frost October 21 · 185 frost-free days · USDA Zone 8b
ZIP 98029 has about 30,600 people, the largest of 2 ZIP codes in Issaquah.
Long season: 185 frost-free days. Spring frost risk spans March 28–May 11 (44 days). Fall frost risk spans October 2–November 8 (37 days).
Frost probability for 98029
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 11 | April 19 | March 28 |
| Fall (first frost) | October 2 | October 21 | November 8 |
Dates come from NOAA 1971–2000 freeze probabilities at SNOQUALMIE FALLS (13.1 km away); the 50% date is the median year.
Frost dates by ZIP code in Issaquah, WA
| ZIP | Last spring frost (50%) | First fall frost (50%) | Zone |
|---|---|---|---|
| 98029 | April 19 | October 21 | 8b |
| 98027 | April 19 | October 21 | 8b |
Which crops fit a 185-day season in Issaquah
In Issaquah (185 frost-free days, a long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 15 | May 3–May 10 | 143 | fits: 80 days to maturity, 143 available after May 3. | Jun 21 |
| Pepper | Mar 8 | May 3–May 10 | 143 | fits: 75 days to maturity, 143 available after May 3. | Jun 26 |
| Lettuce | Feb 22 | Mar 22–Mar 29 | 220 | two-plantings: Plant Mar 22 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Carrots | — | Mar 29–Apr 5 | 227 | fits: 70 days to maturity, 227 available after Mar 29. | Aug 19 |
| Cucumber | Mar 29 | May 3–May 10 | 157 | two-plantings: Plant May 3 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Beans | — | Apr 26–May 10 | 171 | two-plantings: Plant Apr 26 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Peas | — | Feb 22–May 3 | 248 | fits: 65 days to maturity, 248 available after Feb 22. | Aug 10 |
| Zucchini | Apr 5 | May 3–May 10 | 157 | two-plantings: Plant May 3 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Onion | Jan 25 | Mar 22–Apr 5 | 220 | fits: 100 days to maturity, 220 available after Mar 22. | — |
| Spinach | — | Feb 22–Apr 12 | 262 | two-plantings: Plant Feb 22 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Kale | Feb 8 | Mar 22–Apr 5 | 234 | two-plantings: Plant Mar 22 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Broccoli | Feb 22 | Mar 22–Apr 5 | 220 | fits: 80 days to maturity, 220 available after Mar 22. | Jul 26 |
| Cabbage | Feb 22 | Mar 22–Apr 5 | 234 | fits: 70 days to maturity, 234 available after Mar 22. | Aug 19 |
| Radish | — | Feb 22–May 17 | 248 | two-plantings: Plant Feb 22 and again by Sep 19; both mature before Oct 28. | Sep 19 |
| Beets | — | Feb 22–May 17 | 248 | two-plantings: Plant Feb 22 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Potatoes | — | Apr 5–Apr 12 | 206 | fits: 90 days to maturity, 206 available after Apr 5. | — |
| Garlic | — | Oct 21 | 290 | overwinter: Plant Oct 21 to Nov 11; harvest the following summer. | Nov 11 |
| Strawberry | — | Mar 15–May 10 | 241 | perennial: A perennial: plant Mar 15; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 22 | Apr 26–May 3 | 157 | fits: 75 days to maturity, 157 available after Apr 26. | Jul 3 |
| Pumpkin | Apr 5 | May 3–May 3 | 150 | fits: 100 days to maturity, 150 available after May 3. | Jun 8 |
| Cauliflower | Mar 8 | Apr 12–Apr 26 | 199 | fits: 75 days to maturity, 199 available after Apr 12. | Jul 31 |
| Swiss Chard | Feb 22 | Apr 5–Apr 5 | 206 | two-plantings: Plant Apr 5 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Arugula | — | Feb 22–May 17 | 262 | two-plantings: Plant Feb 22 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Brussel Sprouts | Feb 22 | Mar 22–Apr 5 | 234 | fits: 100 days to maturity, 234 available after Mar 22. | Jul 20 |
| Butternut Squash | Apr 5 | May 3–May 10 | 150 | fits: 100 days to maturity, 150 available after May 3. | Jun 8 |
| Eggplant | Mar 1 | May 3–May 10 | 143 | fits: 70 days to maturity, 143 available after May 3. | Jul 1 |
| Okra | Mar 22 | Apr 26–May 3 | 164 | two-plantings: Plant Apr 26 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Basil | Mar 15 | May 10–May 10 | 150 | two-plantings: Plant May 10 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Cilantro | — | Mar 22–Apr 12 | 220 | two-plantings: Plant Mar 22 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Parsley | Feb 8 | Apr 26–May 3 | 185 | fits: 70 days to maturity, 185 available after Apr 26. | Aug 5 |
| Celery | Feb 8 | Apr 26–May 10 | 185 | fits: 120 days to maturity, 185 available after Apr 26. | Jun 16 |
| Scallions | Feb 8 | Mar 22–Apr 5 | 234 | two-plantings: Plant Mar 22 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Turnip | — | Mar 22–Apr 5 | 234 | two-plantings: Plant Mar 22 and again by Sep 8; both mature before Nov 11. | Sep 8 |
| Kohlrabi | — | Mar 8–Mar 22 | 248 | two-plantings: Plant Mar 8 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Bok Choy | Mar 22 | Apr 12–Apr 19 | 199 | two-plantings: Plant Apr 12 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Collards | Feb 8 | Mar 22–Apr 5 | 234 | two-plantings: Plant Mar 22 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Cantaloupe | Apr 5 | May 3–May 10 | 143 | fits: 85 days to maturity, 143 available after May 3. | Jun 16 |
| Chives | Jan 25 | Apr 26–May 3 | 199 | fits: 90 days to maturity, 199 available after Apr 26. | — |
| Dill | — | Feb 22–May 17 | 248 | two-plantings: Plant Feb 22 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Oregano | Feb 8 | Apr 26–May 3 | 199 | fits: 80 days to maturity, 199 available after Apr 26. | — |
| Rosemary | Jan 25 | Apr 26–May 3 | 185 | fits: 80 days to maturity, 185 available after Apr 26. | — |
| Sage | Feb 22 | Apr 26–May 3 | 199 | fits: 75 days to maturity, 199 available after Apr 26. | — |
| Thyme | Feb 8 | Apr 26–May 3 | 199 | fits: 90 days to maturity, 199 available after Apr 26. | — |
| Calendula | Mar 8 | Apr 5–Apr 19 | 206 | two-plantings: Plant Apr 5 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Cosmos | Mar 22 | Apr 19–May 3 | 171 | two-plantings: Plant Apr 19 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Lavender | Jan 25 | Apr 19–May 3 | 206 | fits: 90 days to maturity, 206 available after Apr 19. | — |
| Marigolds | Mar 8 | Apr 19–Apr 26 | 171 | two-plantings: Plant Apr 19 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Melons | Apr 5 | May 3–May 10 | 143 | fits: 85 days to maturity, 143 available after May 3. | Jun 16 |
| Mint | — | Apr 19–May 3 | 206 | fits: 90 days to maturity, 206 available after Apr 19. | — |
| Nasturtiums | Mar 22 | Apr 19–Apr 26 | 171 | two-plantings: Plant Apr 19 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Pole Beans | — | Apr 26–May 10 | 164 | fits: 65 days to maturity, 164 available after Apr 26. | Jul 20 |
| Spaghetti Squash | Apr 5 | May 3–May 10 | 150 | fits: 90 days to maturity, 150 available after May 3. | Jun 18 |
| Sunflowers | — | Apr 19–May 3 | 171 | fits: 70 days to maturity, 171 available after Apr 19. | Jul 15 |
| Tomatillos | Feb 22 | Apr 26–May 3 | 150 | fits: 75 days to maturity, 150 available after Apr 26. | Jun 26 |
| Watermelon | Apr 5 | Apr 26–May 3 | 150 | fits: 80 days to maturity, 150 available after Apr 26. | Jun 21 |
| Yellow Squash | Apr 5 | May 3–May 10 | 157 | two-plantings: Plant May 3 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Zinnias | Mar 22 | Apr 19–May 3 | 171 | two-plantings: Plant Apr 19 and again by Jul 25; both mature before Oct 7. | Jul 25 |
Month by month in Issaquah
| Month | What to do |
|---|---|
| January | Start indoors: Chives (Jan 25), Lavender (Jan 25), Onion (Jan 25), Rosemary (Jan 25). |
| February | Start indoors: Celery (Feb 8), Collards (Feb 8), Kale (Feb 8), Oregano (Feb 8), Parsley (Feb 8), Scallions (Feb 8), +8 more. Direct sow from: Arugula (Feb 22), Beets (Feb 22), Dill (Feb 22), Peas (Feb 22), Radish (Feb 22), Spinach (Feb 22). |
| March | Start indoors: Eggplant (Mar 1), Calendula (Mar 8), Cauliflower (Mar 8), Marigolds (Mar 8), Pepper (Mar 8), Basil (Mar 15), +8 more. Direct sow from: Kohlrabi (Mar 8), Cilantro (Mar 22), Turnip (Mar 22), Carrots (Mar 29). Transplant from: Broccoli (Mar 22), Brussel Sprouts (Mar 22), Cabbage (Mar 22), Collards (Mar 22), Kale (Mar 22), Lettuce (Mar 22), +2 more. Plant: Strawberry (Mar 15). |
| April | Start indoors: Butternut Squash (Apr 5), Cantaloupe (Apr 5), Melons (Apr 5), Pumpkin (Apr 5), Spaghetti Squash (Apr 5), Watermelon (Apr 5), +2 more. Direct sow from: Potatoes (Apr 5), Sunflowers (Apr 19), Beans (Apr 26), Pole Beans (Apr 26). Transplant from: Calendula (Apr 5), Swiss Chard (Apr 5), Bok Choy (Apr 12), Cauliflower (Apr 12), Cosmos (Apr 19), Lavender (Apr 19), +15 more. Last frost around April 19. |
| May | Transplant from: Butternut Squash (May 3), Cantaloupe (May 3), Cucumber (May 3), Eggplant (May 3), Melons (May 3), Pepper (May 3), +6 more. |
| June | Last sowing dates: Butternut Squash (Jun 8), Pumpkin (Jun 8), Cantaloupe (Jun 16), Celery (Jun 16), Melons (Jun 16), Spaghetti Squash (Jun 18), +4 more. |
| July | Last sowing dates: Eggplant (Jul 1), Corn (Jul 3), Sunflowers (Jul 15), Brussel Sprouts (Jul 20), Pole Beans (Jul 20), Basil (Jul 25), +9 more. |
| August | Last sowing dates: Beans (Aug 1), Marigolds (Aug 4), Parsley (Aug 5), Peas (Aug 10), Cabbage (Aug 19), Carrots (Aug 19), +9 more. |
| September | Last sowing dates: Kale (Sep 3), Kohlrabi (Sep 3), Turnip (Sep 8), Arugula (Sep 18), Spinach (Sep 18), Radish (Sep 19). |
| October | Direct sow from: Garlic (Oct 21). First frost around October 21. |
| November | Last sowing dates: Garlic (Nov 11). |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Issaquah, WA (ZIP 98029)?
The median last spring frost date for Issaquah, WA (ZIP code 98029) is around April 19. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before March 28; one in ten it runs past May 11.
What is the first fall frost date in Issaquah, WA?
The median first fall frost date for Issaquah, WA is around October 21. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around October 2 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Issaquah, WA?
The frost-free growing season in Issaquah is about 185 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Issaquah (185 frost-free days, a long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Issaquah, WA?
Issaquah, WA is in USDA hardiness zone 8b (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Issaquah, WA?
Start tomatoes indoors Mar 15 and plant out May 3 in Issaquah. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Issaquah?
Two: plant Mar 22 and again by Aug 30; both mature before Oct 28.
When do I plant garlic in Issaquah?
Oct 21 to Nov 11; it overwinters and is ready the following summer.
Can I get two tomato crops in Issaquah?
Yes: plant out May 3 for a summer crop, and set out a second round of transplants by Jun 21 for a fall crop.
Which nearby ZIP has a longer season?
Bellevue (ZIP 98006) has 198 frost-free days, 13 more than Issaquah (ZIP 98029). See Bellevue ZIP 98006 frost dates
Nearby and related
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