Frost Dates for Kennewick, WA 99338
Kennewick has 3 ZIP codes. The Kennewick, WA frost page lists all of them with their dates.
Last spring frost April 7 · First fall frost October 21 · 197 frost-free days · USDA Zone 7b
ZIP 99338 has about 20,600 people, one of 3 ZIP codes in Kennewick.
Long season: 197 frost-free days. Spring frost risk spans March 18–April 21 (34 days). Fall frost risk spans October 5–November 6 (32 days).
Frost probability for 99338
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | April 21 | April 7 | March 18 |
| Fall (first frost) | October 5 | October 21 | November 6 |
Dates come from NOAA 1971–2000 freeze probabilities at RICHLAND (15.4 km away); the 50% date is the median year.
Which crops fit a 197-day season in Kennewick
In Kennewick (197 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 3 | Apr 21–Apr 28 | 155 | fits: 80 days to maturity, 155 available after Apr 21. | Jun 21 |
| Pepper | Feb 24 | Apr 21–Apr 28 | 155 | fits: 75 days to maturity, 155 available after Apr 21. | Jun 26 |
| Lettuce | Feb 10 | Mar 10–Mar 17 | 232 | two-plantings: Plant Mar 10 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Carrots | — | Mar 17–Mar 24 | 239 | fits: 70 days to maturity, 239 available after Mar 17. | Aug 19 |
| Cucumber | Mar 17 | Apr 21–Apr 28 | 169 | two-plantings: Plant Apr 21 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Beans | — | Apr 14–Apr 28 | 183 | two-plantings: Plant Apr 14 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Peas | — | Feb 10–Apr 21 | 260 | fits: 65 days to maturity, 260 available after Feb 10. | Aug 10 |
| Zucchini | Mar 24 | Apr 21–Apr 28 | 169 | two-plantings: Plant Apr 21 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Onion | Jan 13 | Mar 10–Mar 24 | 232 | fits: 100 days to maturity, 232 available after Mar 10. | — |
| Spinach | — | Feb 10–Mar 31 | 274 | two-plantings: Plant Feb 10 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Kale | Jan 27 | Mar 10–Mar 24 | 246 | two-plantings: Plant Mar 10 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Broccoli | Feb 10 | Mar 10–Mar 24 | 232 | fits: 80 days to maturity, 232 available after Mar 10. | Jul 26 |
| Cabbage | Feb 10 | Mar 10–Mar 24 | 246 | fits: 70 days to maturity, 246 available after Mar 10. | Aug 19 |
| Radish | — | Feb 10–May 5 | 260 | two-plantings: Plant Feb 10 and again by Sep 19; both mature before Oct 28. | Sep 19 |
| Beets | — | Feb 10–May 5 | 260 | two-plantings: Plant Feb 10 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Potatoes | — | Mar 24–Mar 31 | 218 | fits: 90 days to maturity, 218 available after Mar 24. | — |
| Garlic | — | Oct 21 | 302 | overwinter: Plant Oct 21 to Nov 11; harvest the following summer. | Nov 11 |
| Strawberry | — | Mar 3–Apr 28 | 253 | perennial: A perennial: plant Mar 3; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 10 | Apr 14–Apr 21 | 169 | fits: 75 days to maturity, 169 available after Apr 14. | Jul 3 |
| Pumpkin | Mar 24 | Apr 21–Apr 21 | 162 | fits: 100 days to maturity, 162 available after Apr 21. | Jun 8 |
| Cauliflower | Feb 24 | Mar 31–Apr 14 | 211 | fits: 75 days to maturity, 211 available after Mar 31. | Jul 31 |
| Swiss Chard | Feb 10 | Mar 24–Mar 24 | 218 | two-plantings: Plant Mar 24 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Arugula | — | Feb 10–May 5 | 274 | two-plantings: Plant Feb 10 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Brussel Sprouts | Feb 10 | Mar 10–Mar 24 | 246 | fits: 100 days to maturity, 246 available after Mar 10. | Jul 20 |
| Butternut Squash | Mar 24 | Apr 21–Apr 28 | 162 | fits: 100 days to maturity, 162 available after Apr 21. | Jun 8 |
| Eggplant | Feb 17 | Apr 21–Apr 28 | 155 | fits: 70 days to maturity, 155 available after Apr 21. | Jul 1 |
| Okra | Mar 10 | Apr 14–Apr 21 | 176 | two-plantings: Plant Apr 14 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Basil | Mar 3 | Apr 28–Apr 28 | 162 | two-plantings: Plant Apr 28 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Cilantro | — | Mar 10–Mar 31 | 232 | two-plantings: Plant Mar 10 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Parsley | Jan 27 | Apr 14–Apr 21 | 197 | fits: 70 days to maturity, 197 available after Apr 14. | Aug 5 |
| Celery | Jan 27 | Apr 14–Apr 28 | 197 | fits: 120 days to maturity, 197 available after Apr 14. | Jun 16 |
| Scallions | Jan 27 | Mar 10–Mar 24 | 246 | two-plantings: Plant Mar 10 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Turnip | — | Mar 10–Mar 24 | 246 | two-plantings: Plant Mar 10 and again by Sep 8; both mature before Nov 11. | Sep 8 |
| Kohlrabi | — | Feb 24–Mar 10 | 260 | two-plantings: Plant Feb 24 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Bok Choy | Mar 10 | Mar 31–Apr 7 | 211 | two-plantings: Plant Mar 31 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Collards | Jan 27 | Mar 10–Mar 24 | 246 | two-plantings: Plant Mar 10 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Cantaloupe | Mar 24 | Apr 21–Apr 28 | 155 | fits: 85 days to maturity, 155 available after Apr 21. | Jun 16 |
| Chives | Jan 13 | Apr 14–Apr 21 | 211 | fits: 90 days to maturity, 211 available after Apr 14. | — |
| Dill | — | Feb 10–May 5 | 260 | two-plantings: Plant Feb 10 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Oregano | Jan 27 | Apr 14–Apr 21 | 211 | fits: 80 days to maturity, 211 available after Apr 14. | — |
| Rosemary | Jan 13 | Apr 14–Apr 21 | 197 | fits: 80 days to maturity, 197 available after Apr 14. | — |
| Sage | Feb 10 | Apr 14–Apr 21 | 211 | fits: 75 days to maturity, 211 available after Apr 14. | — |
| Thyme | Jan 27 | Apr 14–Apr 21 | 211 | fits: 90 days to maturity, 211 available after Apr 14. | — |
| Calendula | Feb 24 | Mar 24–Apr 7 | 218 | two-plantings: Plant Mar 24 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Cosmos | Mar 10 | Apr 7–Apr 21 | 183 | two-plantings: Plant Apr 7 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Lavender | Jan 13 | Apr 7–Apr 21 | 218 | fits: 90 days to maturity, 218 available after Apr 7. | — |
| Marigolds | Feb 24 | Apr 7–Apr 14 | 183 | two-plantings: Plant Apr 7 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Melons | Mar 24 | Apr 21–Apr 28 | 155 | fits: 85 days to maturity, 155 available after Apr 21. | Jun 16 |
| Mint | — | Apr 7–Apr 21 | 218 | fits: 90 days to maturity, 218 available after Apr 7. | — |
| Nasturtiums | Mar 10 | Apr 7–Apr 14 | 183 | two-plantings: Plant Apr 7 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Pole Beans | — | Apr 14–Apr 28 | 176 | fits: 65 days to maturity, 176 available after Apr 14. | Jul 20 |
| Spaghetti Squash | Mar 24 | Apr 21–Apr 28 | 162 | fits: 90 days to maturity, 162 available after Apr 21. | Jun 18 |
| Sunflowers | — | Apr 7–Apr 21 | 183 | fits: 70 days to maturity, 183 available after Apr 7. | Jul 15 |
| Tomatillos | Feb 10 | Apr 14–Apr 21 | 162 | fits: 75 days to maturity, 162 available after Apr 14. | Jun 26 |
| Watermelon | Mar 24 | Apr 14–Apr 21 | 162 | fits: 80 days to maturity, 162 available after Apr 14. | Jun 21 |
| Yellow Squash | Mar 24 | Apr 21–Apr 28 | 169 | two-plantings: Plant Apr 21 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Zinnias | Mar 10 | Apr 7–Apr 21 | 183 | two-plantings: Plant Apr 7 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 13), Lavender (Jan 13), Onion (Jan 13), Rosemary (Jan 13), Celery (Jan 27), Collards (Jan 27), +5 more. |
| February | Start indoors: Broccoli (Feb 10), Brussel Sprouts (Feb 10), Cabbage (Feb 10), Lettuce (Feb 10), Sage (Feb 10), Swiss Chard (Feb 10), +6 more. Direct sow from: Arugula (Feb 10), Beets (Feb 10), Dill (Feb 10), Peas (Feb 10), Radish (Feb 10), Spinach (Feb 10), +1 more. |
| March | Start indoors: Basil (Mar 3), Tomato (Mar 3), Bok Choy (Mar 10), Corn (Mar 10), Cosmos (Mar 10), Nasturtiums (Mar 10), +11 more. Direct sow from: Cilantro (Mar 10), Turnip (Mar 10), Carrots (Mar 17), Potatoes (Mar 24). Transplant from: Broccoli (Mar 10), Brussel Sprouts (Mar 10), Cabbage (Mar 10), Collards (Mar 10), Kale (Mar 10), Lettuce (Mar 10), +6 more. Plant: Strawberry (Mar 3). |
| April | Direct sow from: Sunflowers (Apr 7), Beans (Apr 14), Pole Beans (Apr 14). Transplant from: Cosmos (Apr 7), Lavender (Apr 7), Marigolds (Apr 7), Mint (Apr 7), Nasturtiums (Apr 7), Zinnias (Apr 7), +23 more. Last frost around April 7. |
| 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 99338)?
The median last spring frost date for Kennewick, WA (ZIP code 99338) is around April 7. 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 21.
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 197 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 (197 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 3 and plant out Apr 21 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 10 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 21 for a summer crop, and set out a second round of transplants by Jun 21 for a fall crop.
Nearby and related
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