Frost dates · USDA zone 4b
Frost dates for Eau Claire, WI
Eau Claire, WI sees its last 32 °F night of spring around May 8 and its first of fall around October 4 — a 149-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 | Apr 24 | Oct 17 |
| Median — 1 year in 2 | May 8 | Oct 4 |
| 1 year in 10 | May 21 | Sep 20 |
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: 149 days median, at least 128 in 9 years of 10, at least 166 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 Apr 27 and first of Oct 15.
Eau Claire planting calendar, 2027
Every row runs from the median last frost (May 8) and median first frost (Oct 4) 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) | Feb 13 | Apr 10 | Jul 29 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | May 8 | Jun 7 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Apr 24 | Apr 24 | Jun 8 | 45 from sow |
| Genovese BasilGenovese | Apr 10 | May 22 | Jul 21 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Mar 13 | May 15 | Jul 29 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Feb 27 | May 22 | Aug 25 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Mar 13 | May 15 | Jul 29 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Mar 13 | May 15 | Aug 3 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Mar 13 | May 15 | Aug 3 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Apr 24 | Apr 24 | Jul 3 | 70 from sow |
| TomatilloToma Verde | Mar 27 | May 15 | Jul 24 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Mar 27 | May 15 | Jul 29 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Mar 27 | May 15 | Aug 3 | 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 Eau Claire grow?
Each sauce, scheduled for a Eau Claire container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Eau Claire frost questions
When is the last frost in Eau Claire, WI?
The median last 32 °F freeze at EAU CLAIRE RGNL AP, WI is May 8: half of years see a later one. One year in ten, a freeze still comes after May 21; nine years in ten, it comes after April 24. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Eau Claire, WI?
The median first 32 °F freeze of fall is October 4. One year in ten it arrives before September 20; nine years in ten, before October 17.
How long is the growing season in Eau Claire, WI?
149 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 128 days; one year in ten, at least 166 days.
What growing zone is Eau Claire, WI?
USDA hardiness zone 4b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 54703. 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 Eau Claire, WI?
Start Roma VF (determinate paste) seeds indoors around Mar 27 and transplant around May 15, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for May 21. First ripe fruit lands around Jul 29.
When should I plant peppers in Eau Claire, WI?
Sow jalapeño indoors on a heat mat around Mar 13; transplant no earlier than May 15, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jul 29.
Nearby in Wisconsin
- La Crosselast frost Apr 23
- Oshkoshlast frost Apr 24
- Appletonlast frost May 4
- Madisonlast frost May 1
- Fond du Laclast frost May 1
- Green Baylast frost May 7
All Wisconsin frost dates → · How frost-date math drives a sowing calendar →