Frost dates · USDA zone 5b
Frost dates for Waukesha, WI
Waukesha, WI sees its last 32 °F night of spring around April 30 and its first of fall around October 14 — a 164-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 16 | Oct 27 |
| Median — 1 year in 2 | Apr 30 | Oct 14 |
| 1 year in 10 | May 15 | Sep 28 |
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: 164 days median, at least 144 in 9 years of 10, at least 184 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 19 and first of Oct 25.
Waukesha planting calendar, 2027
Every row runs from the median last frost (Apr 30) and median first frost (Oct 14) 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 5 | Apr 2 | Jul 21 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Apr 30 | May 30 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Apr 16 | Apr 16 | May 31 | 45 from sow |
| Genovese BasilGenovese | Apr 2 | May 14 | Jul 13 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Mar 5 | May 7 | Jul 21 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Feb 19 | May 14 | Aug 17 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Mar 5 | May 7 | Jul 21 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Mar 5 | May 7 | Jul 26 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Mar 5 | May 7 | Jul 26 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Apr 16 | Apr 16 | Jun 25 | 70 from sow |
| TomatilloToma Verde | Mar 19 | May 7 | Jul 16 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Mar 19 | May 7 | Jul 21 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Mar 19 | May 7 | Jul 26 | 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 Waukesha grow?
Each sauce, scheduled for a Waukesha container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Waukesha frost questions
When is the last frost in Waukesha, WI?
The median last 32 °F freeze at BROOKFIELD WWTP, WI is April 30: half of years see a later one. One year in ten, a freeze still comes after May 15; nine years in ten, it comes after April 16. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Waukesha, WI?
The median first 32 °F freeze of fall is October 14. One year in ten it arrives before September 28; nine years in ten, before October 27.
How long is the growing season in Waukesha, WI?
164 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 144 days; one year in ten, at least 184 days.
What growing zone is Waukesha, WI?
USDA hardiness zone 5b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 53186. 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 Waukesha, WI?
Start Roma VF (determinate paste) seeds indoors around Mar 19 and transplant around May 7, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for May 15. First ripe fruit lands around Jul 21.
When should I plant peppers in Waukesha, WI?
Sow jalapeño indoors on a heat mat around Mar 5; transplant no earlier than May 7, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jul 21.
Nearby in Wisconsin
- Brookfieldlast frost Apr 26
- West Allislast frost Apr 26
- Wauwatosalast frost Apr 26
- Milwaukeelast frost Apr 26
- Racinelast frost Apr 24
- Kenoshalast frost Apr 28
All Wisconsin frost dates → · How frost-date math drives a sowing calendar →