Frost dates · USDA zone 7b
Frost dates for Kennewick, WA
Kennewick, WA sees its last 32 °F night of spring around March 28 and its first of fall around October 30 — a 216-day freeze-free season in a typical year.
Pick a sauce; the Plan Builder runs this station's dates and hands back the calendar, plant count and gear list.
Freeze odds, by date
| Odds | Last spring freeze after | First fall freeze before |
|---|---|---|
| 9 years in 10 | Mar 9 | Nov 15 |
| Median — 1 year in 2 | Mar 28 | Oct 30 |
| 1 year in 10 | Apr 10 | Oct 18 |
The top row is the risky edge: in 9 years of 10 a spring freeze still comes after it, so tender transplants set out then need cover. The bottom row is the cautious date — only 1 year in 10 freezes after it — and the one to plan uncovered tender transplants against. Freeze-free season: 216 days median, at least 196 in 9 years of 10, at least 239 days in 1 year of 10. NOAA ranks season length year by year, so it is not the gap between two rows above. A hard freeze (28 °F) has a median last date of Mar 8 and first of Nov 11.
Kennewick planting calendar, 2027
Every row runs from the median last frost (Mar 28) and median first frost (Oct 30) above, using each cultivar's days to maturity. Same engine as the Plan Builder.
| Crop | Start indoors | Transplant / plant | First harvest | Days |
|---|---|---|---|---|
| Hardneck GarlicSiberian (porcelain hardneck) | — | Oct 15prior fall | Jun 12 | 240 from sow |
| Spanish OnionYellow Sweet Spanish (long-day) | Jan 3 | Feb 28 | Jun 18 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Mar 28 | Apr 27 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Mar 14 | Mar 14 | Apr 28 | 45 from sow |
| Genovese BasilGenovese | Feb 28 | Apr 11 | Jun 10 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Jan 31 | Apr 4 | Jun 18 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Jan 17 | Apr 11 | Jul 15 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Jan 31 | Apr 4 | Jun 18 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Jan 31 | Apr 4 | Jun 23 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Jan 31 | Apr 4 | Jun 23 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Mar 14 | Mar 14 | May 23 | 70 from sow |
| TomatilloToma Verde | Feb 14 | Apr 4 | Jun 13 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Feb 14 | Apr 4 | Jun 18 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Feb 14 | Apr 4 | Jun 23 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost: start that crop indoors on time or cover it in fall.
What sauce can Kennewick grow?
Each sauce, scheduled for a Kennewick container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Kennewick frost questions
When is the last frost in Kennewick, WA?
The median last 32 °F freeze at KENNEWICK, WA is March 28: half of years see a later one. One year in ten, a freeze still comes after April 10; nine years in ten, it comes after March 9. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Kennewick, WA?
The median first 32 °F freeze of fall is October 30. One year in ten it arrives before October 18; nine years in ten, before November 15.
How long is the growing season in Kennewick, WA?
216 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 196 days; one year in ten, at least 239 days.
What growing zone is Kennewick, WA?
USDA hardiness zone 7b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 99336. A zone describes the coldest winter night, not when frost ends, so it is the wrong number for a planting calendar — the frost dates on this page are the right one.
When should I plant tomatoes in Kennewick, WA?
Start Roma VF (determinate paste) seeds indoors around Feb 14 and transplant around Apr 4, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Apr 10. First ripe fruit lands around Jun 18.
When should I plant peppers in Kennewick, WA?
Sow jalapeño indoors on a heat mat around Jan 31; transplant no earlier than Apr 4, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jun 18.
Nearby in Washington
- Pascolast frost Mar 28
- Richlandlast frost Apr 6
- Yakimalast frost Apr 8
- Spokanelast frost Apr 26
- Spokane Valleylast frost Apr 26
- Puyalluplast frost Apr 11
All Washington frost dates → · How frost-date math drives a sowing calendar →