Frost Dates for Sunnyside, WA 98944
Last spring frost April 25 · First fall frost October 9 · 167 frost-free days · USDA Zone 7b
ZIP 98944 has about 22,800 people.
Moderate season: 167 frost-free days. Spring frost risk spans April 10–May 9 (29 days). Fall frost risk spans September 25–October 25 (30 days).
Frost probability for 98944
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 9 | April 25 | April 10 |
| Fall (first frost) | September 25 | October 9 | October 25 |
Dates come from NOAA 1971–2000 freeze probabilities at SMYRNA (37.4 km away); the 50% date is the median year.
Which crops fit a 167-day season in Sunnyside
In Sunnyside (167 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 21 | May 9–May 16 | 125 | fits: 80 days to maturity, 125 available after May 9. | Jun 9 |
| Pepper | Mar 14 | May 9–May 16 | 125 | fits: 75 days to maturity, 125 available after May 9. | Jun 14 |
| Lettuce | Feb 28 | Mar 28–Apr 4 | 202 | two-plantings: Plant Mar 28 and again by Aug 18; both mature before Oct 16. | Aug 18 |
| Carrots | — | Apr 4–Apr 11 | 209 | fits: 70 days to maturity, 209 available after Apr 4. | Aug 7 |
| Cucumber | Apr 4 | May 9–May 16 | 139 | two-plantings: Plant May 9 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Beans | — | May 2–May 16 | 153 | two-plantings: Plant May 2 and again by Jul 20; both mature before Oct 2. | Jul 20 |
| Peas | — | Feb 28–May 9 | 230 | fits: 65 days to maturity, 230 available after Feb 28. | Jul 29 |
| Zucchini | Apr 11 | May 9–May 16 | 139 | two-plantings: Plant May 9 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Onion | Jan 31 | Mar 28–Apr 11 | 202 | fits: 100 days to maturity, 202 available after Mar 28. | — |
| Spinach | — | Feb 28–Apr 18 | 244 | two-plantings: Plant Feb 28 and again by Sep 6; both mature before Oct 30. | Sep 6 |
| Kale | Feb 14 | Mar 28–Apr 11 | 216 | two-plantings: Plant Mar 28 and again by Aug 22; both mature before Oct 30. | Aug 22 |
| Broccoli | Feb 28 | Mar 28–Apr 11 | 202 | fits: 80 days to maturity, 202 available after Mar 28. | Jul 14 |
| Cabbage | Feb 28 | Mar 28–Apr 11 | 216 | fits: 70 days to maturity, 216 available after Mar 28. | Aug 7 |
| Radish | — | Feb 28–May 23 | 230 | two-plantings: Plant Feb 28 and again by Sep 7; both mature before Oct 16. | Sep 7 |
| Beets | — | Feb 28–May 23 | 230 | two-plantings: Plant Feb 28 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Potatoes | — | Apr 11–Apr 18 | 188 | fits: 90 days to maturity, 188 available after Apr 11. | — |
| Garlic | — | Oct 9 | 272 | overwinter: Plant Oct 9 to Oct 30; harvest the following summer. | Oct 30 |
| Strawberry | — | Mar 21–May 16 | 223 | perennial: A perennial: plant Mar 21; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 28 | May 2–May 9 | 139 | fits: 75 days to maturity, 139 available after May 2. | Jun 21 |
| Pumpkin | Apr 11 | May 9–May 9 | 132 | fits: 100 days to maturity, 132 available after May 9. | May 27 |
| Cauliflower | Mar 14 | Apr 18–May 2 | 181 | fits: 75 days to maturity, 181 available after Apr 18. | Jul 19 |
| Swiss Chard | Feb 28 | Apr 11–Apr 11 | 188 | two-plantings: Plant Apr 11 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Arugula | — | Feb 28–May 23 | 244 | two-plantings: Plant Feb 28 and again by Sep 6; both mature before Oct 30. | Sep 6 |
| Brussel Sprouts | Feb 28 | Mar 28–Apr 11 | 216 | fits: 100 days to maturity, 216 available after Mar 28. | Jul 8 |
| Butternut Squash | Apr 11 | May 9–May 16 | 132 | fits: 100 days to maturity, 132 available after May 9. | May 27 |
| Eggplant | Mar 7 | May 9–May 16 | 125 | fits: 70 days to maturity, 125 available after May 9. | Jun 19 |
| Okra | Mar 28 | May 2–May 9 | 146 | two-plantings: Plant May 2 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Basil | Mar 21 | May 16–May 16 | 132 | fits: 60 days to maturity, 132 available after May 16. | Jul 13 |
| Cilantro | — | Mar 28–Apr 18 | 202 | two-plantings: Plant Mar 28 and again by Aug 13; both mature before Oct 16. | Aug 13 |
| Parsley | Feb 14 | May 2–May 9 | 167 | fits: 70 days to maturity, 167 available after May 2. | Jul 24 |
| Celery | Feb 14 | May 2–May 16 | 167 | fits: 120 days to maturity, 167 available after May 2. | Jun 4 |
| Scallions | Feb 14 | Mar 28–Apr 11 | 216 | two-plantings: Plant Mar 28 and again by Aug 17; both mature before Oct 30. | Aug 17 |
| Turnip | — | Mar 28–Apr 11 | 216 | two-plantings: Plant Mar 28 and again by Aug 27; both mature before Oct 30. | Aug 27 |
| Kohlrabi | — | Mar 14–Mar 28 | 230 | two-plantings: Plant Mar 14 and again by Aug 22; both mature before Oct 30. | Aug 22 |
| Bok Choy | Mar 28 | Apr 18–Apr 25 | 181 | two-plantings: Plant Apr 18 and again by Aug 18; both mature before Oct 16. | Aug 18 |
| Collards | Feb 14 | Mar 28–Apr 11 | 216 | two-plantings: Plant Mar 28 and again by Aug 17; both mature before Oct 30. | Aug 17 |
| Cantaloupe | Apr 11 | May 9–May 16 | 125 | fits: 85 days to maturity, 125 available after May 9. | Jun 4 |
| Chives | Jan 31 | May 2–May 9 | 181 | fits: 90 days to maturity, 181 available after May 2. | — |
| Dill | — | Feb 28–May 23 | 230 | two-plantings: Plant Feb 28 and again by Aug 8; both mature before Oct 16. | Aug 8 |
| Oregano | Feb 14 | May 2–May 9 | 181 | fits: 80 days to maturity, 181 available after May 2. | — |
| Rosemary | Jan 31 | May 2–May 9 | 167 | fits: 80 days to maturity, 167 available after May 2. | — |
| Sage | Feb 28 | May 2–May 9 | 181 | fits: 75 days to maturity, 181 available after May 2. | — |
| Thyme | Feb 14 | May 2–May 9 | 181 | fits: 90 days to maturity, 181 available after May 2. | — |
| Calendula | Mar 14 | Apr 11–Apr 25 | 188 | two-plantings: Plant Apr 11 and again by Aug 13; both mature before Oct 16. | Aug 13 |
| Cosmos | Mar 28 | Apr 25–May 9 | 153 | two-plantings: Plant Apr 25 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Lavender | Jan 31 | Apr 25–May 9 | 188 | fits: 90 days to maturity, 188 available after Apr 25. | — |
| Marigolds | Mar 14 | Apr 25–May 2 | 153 | two-plantings: Plant Apr 25 and again by Jul 23; both mature before Sep 25. | Jul 23 |
| Melons | Apr 11 | May 9–May 16 | 125 | fits: 85 days to maturity, 125 available after May 9. | Jun 4 |
| Mint | — | Apr 25–May 9 | 188 | fits: 90 days to maturity, 188 available after Apr 25. | — |
| Nasturtiums | Mar 28 | Apr 25–May 2 | 153 | two-plantings: Plant Apr 25 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Pole Beans | — | May 2–May 16 | 146 | fits: 65 days to maturity, 146 available after May 2. | Jul 8 |
| Spaghetti Squash | Apr 11 | May 9–May 16 | 132 | fits: 90 days to maturity, 132 available after May 9. | Jun 6 |
| Sunflowers | — | Apr 25–May 9 | 153 | fits: 70 days to maturity, 153 available after Apr 25. | Jul 3 |
| Tomatillos | Feb 28 | May 2–May 9 | 132 | fits: 75 days to maturity, 132 available after May 2. | Jun 14 |
| Watermelon | Apr 11 | May 2–May 9 | 132 | fits: 80 days to maturity, 132 available after May 2. | Jun 9 |
| Yellow Squash | Apr 11 | May 9–May 16 | 139 | two-plantings: Plant May 9 and again by Jul 18; both mature before Sep 25. | Jul 18 |
| Zinnias | Mar 28 | Apr 25–May 9 | 153 | two-plantings: Plant Apr 25 and again by Jul 13; both mature before Sep 25. | Jul 13 |
Month by month in Sunnyside
| Month | What to do |
|---|---|
| January | Start indoors: Chives (Jan 31), Lavender (Jan 31), Onion (Jan 31), Rosemary (Jan 31). |
| February | Start indoors: Celery (Feb 14), Collards (Feb 14), Kale (Feb 14), Oregano (Feb 14), Parsley (Feb 14), Scallions (Feb 14), +8 more. Direct sow from: Arugula (Feb 28), Beets (Feb 28), Dill (Feb 28), Peas (Feb 28), Radish (Feb 28), Spinach (Feb 28). |
| March | Start indoors: Eggplant (Mar 7), Calendula (Mar 14), Cauliflower (Mar 14), Marigolds (Mar 14), Pepper (Mar 14), Basil (Mar 21), +7 more. Direct sow from: Kohlrabi (Mar 14), Cilantro (Mar 28), Turnip (Mar 28). Transplant from: Broccoli (Mar 28), Brussel Sprouts (Mar 28), Cabbage (Mar 28), Collards (Mar 28), Kale (Mar 28), Lettuce (Mar 28), +2 more. Plant: Strawberry (Mar 21). |
| April | Start indoors: Cucumber (Apr 4), Butternut Squash (Apr 11), Cantaloupe (Apr 11), Melons (Apr 11), Pumpkin (Apr 11), Spaghetti Squash (Apr 11), +3 more. Direct sow from: Carrots (Apr 4), Potatoes (Apr 11), Sunflowers (Apr 25). Transplant from: Calendula (Apr 11), Swiss Chard (Apr 11), Bok Choy (Apr 18), Cauliflower (Apr 18), Cosmos (Apr 25), Lavender (Apr 25), +4 more. Last frost around April 25. |
| May | Direct sow from: Beans (May 2), Pole Beans (May 2). Transplant from: Celery (May 2), Chives (May 2), Corn (May 2), Okra (May 2), Oregano (May 2), Parsley (May 2), +17 more. Last sowing dates: Butternut Squash (May 27), Pumpkin (May 27). |
| June | Last sowing dates: Cantaloupe (Jun 4), Celery (Jun 4), Melons (Jun 4), Spaghetti Squash (Jun 6), Tomato (Jun 9), Watermelon (Jun 9), +4 more. |
| July | Last sowing dates: Sunflowers (Jul 3), Brussel Sprouts (Jul 8), Pole Beans (Jul 8), Basil (Jul 13), Cosmos (Jul 13), Cucumber (Jul 13), +11 more. |
| August | Last sowing dates: Cabbage (Aug 7), Carrots (Aug 7), Beets (Aug 8), Dill (Aug 8), Swiss Chard (Aug 8), Calendula (Aug 13), +8 more. |
| September | Last sowing dates: Arugula (Sep 6), Spinach (Sep 6), Radish (Sep 7). |
| October | Direct sow from: Garlic (Oct 9). First frost around October 9. Last sowing dates: Garlic (Oct 30). |
| November | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| 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 Sunnyside, WA (ZIP 98944)?
The median last spring frost date for Sunnyside, WA (ZIP code 98944) is around April 25. 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 April 10; one in ten it runs past May 9.
What is the first fall frost date in Sunnyside, WA?
The median first fall frost date for Sunnyside, WA is around October 9. 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 September 25 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Sunnyside, WA?
The frost-free growing season in Sunnyside is about 167 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 Sunnyside (167 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Sunnyside, WA?
Sunnyside, 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 Sunnyside, WA?
Start tomatoes indoors Mar 21 and plant out May 9 in Sunnyside. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Sunnyside?
Two: plant Mar 28 and again by Aug 18; both mature before Oct 16.
When do I plant garlic in Sunnyside?
Oct 9 to Oct 30; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
West Richland (ZIP 99353) has 197 frost-free days, 30 more than Sunnyside (ZIP 98944). See West Richland ZIP 99353 frost dates
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