Frost Dates for Kennewick, WA 99337
Kennewick has 3 ZIP codes. The Kennewick, WA frost page lists all of them with their dates.
Last spring frost April 6 · First fall frost October 21 · 198 frost-free days · USDA Zone 7b
ZIP 99337 has about 33,300 people, one of 3 ZIP codes in Kennewick.
Long season: 198 frost-free days. Spring frost risk spans March 18–April 22 (35 days). Fall frost risk spans October 5–November 6 (32 days).
Frost probability for 99337
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | April 22 | April 6 | March 18 |
| Fall (first frost) | October 5 | October 21 | November 6 |
Dates come from NOAA 1971–2000 freeze probabilities at ICE HARBOR DAM (26.1 km away); the 50% date is the median year.
Which crops fit a 198-day season in Kennewick
In Kennewick (198 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 2 | Apr 20–Apr 27 | 156 | fits: 80 days to maturity, 156 available after Apr 20. | Jun 21 |
| Pepper | Feb 23 | Apr 20–Apr 27 | 156 | fits: 75 days to maturity, 156 available after Apr 20. | Jun 26 |
| Lettuce | Feb 9 | Mar 9–Mar 16 | 233 | two-plantings: Plant Mar 9 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Carrots | — | Mar 16–Mar 23 | 240 | fits: 70 days to maturity, 240 available after Mar 16. | Aug 19 |
| Cucumber | Mar 16 | Apr 20–Apr 27 | 170 | two-plantings: Plant Apr 20 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Beans | — | Apr 13–Apr 27 | 184 | two-plantings: Plant Apr 13 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Peas | — | Feb 9–Apr 20 | 261 | fits: 65 days to maturity, 261 available after Feb 9. | Aug 10 |
| Zucchini | Mar 23 | Apr 20–Apr 27 | 170 | two-plantings: Plant Apr 20 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Onion | Jan 12 | Mar 9–Mar 23 | 233 | fits: 100 days to maturity, 233 available after Mar 9. | — |
| Spinach | — | Feb 9–Mar 30 | 275 | two-plantings: Plant Feb 9 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Kale | Jan 26 | Mar 9–Mar 23 | 247 | two-plantings: Plant Mar 9 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Broccoli | Feb 9 | Mar 9–Mar 23 | 233 | fits: 80 days to maturity, 233 available after Mar 9. | Jul 26 |
| Cabbage | Feb 9 | Mar 9–Mar 23 | 247 | fits: 70 days to maturity, 247 available after Mar 9. | Aug 19 |
| Radish | — | Feb 9–May 4 | 261 | two-plantings: Plant Feb 9 and again by Sep 19; both mature before Oct 28. | Sep 19 |
| Beets | — | Feb 9–May 4 | 261 | two-plantings: Plant Feb 9 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Potatoes | — | Mar 23–Mar 30 | 219 | fits: 90 days to maturity, 219 available after Mar 23. | — |
| Garlic | — | Oct 21 | 303 | overwinter: Plant Oct 21 to Nov 11; harvest the following summer. | Nov 11 |
| Strawberry | — | Mar 2–Apr 27 | 254 | perennial: A perennial: plant Mar 2; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 9 | Apr 13–Apr 20 | 170 | fits: 75 days to maturity, 170 available after Apr 13. | Jul 3 |
| Pumpkin | Mar 23 | Apr 20–Apr 20 | 163 | fits: 100 days to maturity, 163 available after Apr 20. | Jun 8 |
| Cauliflower | Feb 23 | Mar 30–Apr 13 | 212 | fits: 75 days to maturity, 212 available after Mar 30. | Jul 31 |
| Swiss Chard | Feb 9 | Mar 23–Mar 23 | 219 | two-plantings: Plant Mar 23 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Arugula | — | Feb 9–May 4 | 275 | two-plantings: Plant Feb 9 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Brussel Sprouts | Feb 9 | Mar 9–Mar 23 | 247 | fits: 100 days to maturity, 247 available after Mar 9. | Jul 20 |
| Butternut Squash | Mar 23 | Apr 20–Apr 27 | 163 | fits: 100 days to maturity, 163 available after Apr 20. | Jun 8 |
| Eggplant | Feb 16 | Apr 20–Apr 27 | 156 | fits: 70 days to maturity, 156 available after Apr 20. | Jul 1 |
| Okra | Mar 9 | Apr 13–Apr 20 | 177 | two-plantings: Plant Apr 13 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Basil | Mar 2 | Apr 27–Apr 27 | 163 | two-plantings: Plant Apr 27 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Cilantro | — | Mar 9–Mar 30 | 233 | two-plantings: Plant Mar 9 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Parsley | Jan 26 | Apr 13–Apr 20 | 198 | fits: 70 days to maturity, 198 available after Apr 13. | Aug 5 |
| Celery | Jan 26 | Apr 13–Apr 27 | 198 | fits: 120 days to maturity, 198 available after Apr 13. | Jun 16 |
| Scallions | Jan 26 | Mar 9–Mar 23 | 247 | two-plantings: Plant Mar 9 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Turnip | — | Mar 9–Mar 23 | 247 | two-plantings: Plant Mar 9 and again by Sep 8; both mature before Nov 11. | Sep 8 |
| Kohlrabi | — | Feb 23–Mar 9 | 261 | two-plantings: Plant Feb 23 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Bok Choy | Mar 9 | Mar 30–Apr 6 | 212 | two-plantings: Plant Mar 30 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Collards | Jan 26 | Mar 9–Mar 23 | 247 | two-plantings: Plant Mar 9 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Cantaloupe | Mar 23 | Apr 20–Apr 27 | 156 | fits: 85 days to maturity, 156 available after Apr 20. | Jun 16 |
| Chives | Jan 12 | Apr 13–Apr 20 | 212 | fits: 90 days to maturity, 212 available after Apr 13. | — |
| Dill | — | Feb 9–May 4 | 261 | two-plantings: Plant Feb 9 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Oregano | Jan 26 | Apr 13–Apr 20 | 212 | fits: 80 days to maturity, 212 available after Apr 13. | — |
| Rosemary | Jan 12 | Apr 13–Apr 20 | 198 | fits: 80 days to maturity, 198 available after Apr 13. | — |
| Sage | Feb 9 | Apr 13–Apr 20 | 212 | fits: 75 days to maturity, 212 available after Apr 13. | — |
| Thyme | Jan 26 | Apr 13–Apr 20 | 212 | fits: 90 days to maturity, 212 available after Apr 13. | — |
| Calendula | Feb 23 | Mar 23–Apr 6 | 219 | two-plantings: Plant Mar 23 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Cosmos | Mar 9 | Apr 6–Apr 20 | 184 | two-plantings: Plant Apr 6 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Lavender | Jan 12 | Apr 6–Apr 20 | 219 | fits: 90 days to maturity, 219 available after Apr 6. | — |
| Marigolds | Feb 23 | Apr 6–Apr 13 | 184 | two-plantings: Plant Apr 6 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Melons | Mar 23 | Apr 20–Apr 27 | 156 | fits: 85 days to maturity, 156 available after Apr 20. | Jun 16 |
| Mint | — | Apr 6–Apr 20 | 219 | fits: 90 days to maturity, 219 available after Apr 6. | — |
| Nasturtiums | Mar 9 | Apr 6–Apr 13 | 184 | two-plantings: Plant Apr 6 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Pole Beans | — | Apr 13–Apr 27 | 177 | fits: 65 days to maturity, 177 available after Apr 13. | Jul 20 |
| Spaghetti Squash | Mar 23 | Apr 20–Apr 27 | 163 | fits: 90 days to maturity, 163 available after Apr 20. | Jun 18 |
| Sunflowers | — | Apr 6–Apr 20 | 184 | fits: 70 days to maturity, 184 available after Apr 6. | Jul 15 |
| Tomatillos | Feb 9 | Apr 13–Apr 20 | 163 | fits: 75 days to maturity, 163 available after Apr 13. | Jun 26 |
| Watermelon | Mar 23 | Apr 13–Apr 20 | 163 | fits: 80 days to maturity, 163 available after Apr 13. | Jun 21 |
| Yellow Squash | Mar 23 | Apr 20–Apr 27 | 170 | two-plantings: Plant Apr 20 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Zinnias | Mar 9 | Apr 6–Apr 20 | 184 | two-plantings: Plant Apr 6 and again by Jul 25; both mature before Oct 7. | Jul 25 |
Month by month in Kennewick
| Month | What to do |
|---|---|
| January | Start indoors: Chives (Jan 12), Lavender (Jan 12), Onion (Jan 12), Rosemary (Jan 12), Celery (Jan 26), Collards (Jan 26), +5 more. |
| February | Start indoors: Broccoli (Feb 9), Brussel Sprouts (Feb 9), Cabbage (Feb 9), Lettuce (Feb 9), Sage (Feb 9), Swiss Chard (Feb 9), +6 more. Direct sow from: Arugula (Feb 9), Beets (Feb 9), Dill (Feb 9), Peas (Feb 9), Radish (Feb 9), Spinach (Feb 9), +1 more. |
| March | Start indoors: Basil (Mar 2), Tomato (Mar 2), Bok Choy (Mar 9), Corn (Mar 9), Cosmos (Mar 9), Nasturtiums (Mar 9), +11 more. Direct sow from: Cilantro (Mar 9), Turnip (Mar 9), Carrots (Mar 16), Potatoes (Mar 23). Transplant from: Broccoli (Mar 9), Brussel Sprouts (Mar 9), Cabbage (Mar 9), Collards (Mar 9), Kale (Mar 9), Lettuce (Mar 9), +6 more. Plant: Strawberry (Mar 2). |
| April | Direct sow from: Sunflowers (Apr 6), Beans (Apr 13), Pole Beans (Apr 13). Transplant from: Cosmos (Apr 6), Lavender (Apr 6), Marigolds (Apr 6), Mint (Apr 6), Nasturtiums (Apr 6), Zinnias (Apr 6), +23 more. Last frost around April 6. |
| May | Frost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini. |
| 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 Kennewick, WA (ZIP 99337)?
The median last spring frost date for Kennewick, WA (ZIP code 99337) is around April 6. 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 18; one in ten it runs past April 22.
What is the first fall frost date in Kennewick, WA?
The median first fall frost date for Kennewick, 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 5 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Kennewick, WA?
The frost-free growing season in Kennewick is about 198 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 Kennewick (198 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 Kennewick, WA?
Kennewick, WA is in USDA hardiness zone 7b (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 Kennewick, WA?
Start tomatoes indoors Mar 2 and plant out Apr 20 in Kennewick. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Kennewick?
Two: plant Mar 9 and again by Aug 30; both mature before Oct 28.
When do I plant garlic in Kennewick?
Oct 21 to Nov 11; it overwinters and is ready the following summer.
Can I get two tomato crops in Kennewick?
Yes: plant out Apr 20 for a summer crop, and set out a second round of transplants by Jun 21 for a fall crop.
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