Last frost date in Waukesha, WI

Average last frost
May 1

Expect the last frost in Waukesha around May 1. Frost after May 18 happens in only one year out of ten. The first fall frost usually arrives about October 13, which leaves 162 frost-free days. An early freeze before September 29 happens one year in ten.

Safe after (10% risk)
May 18
Average first frost
Oct 13
Frost-free season
162 days
Hard freeze (28°F) ends
Apr 19
Next 7 nights in Waukesha

No frost in the next 7 nights

Later than usual: the average first frost here is October 13.

National Weather Service forecast, updated Oct 22, 12:57 UTC

  1. ThuOct 2248°
  2. FriOct 2349°
  3. SatOct 2452°
  4. SunOct 2550°
  5. MonOct 2646°
  6. TueOct 2743°
  7. WedOct 2844°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost May 1First frost Oct 13162 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND162 frost-free days
Frost risk through the year at Waukesha Wwtp, 0.3 miles from Waukesha.

Planting calendar for Waukesha

Windows count forward or back from the average frost dates above. Click a crop for dates across Wisconsin.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesMay 8–May 22
PumpkinsMay 15–May 29
SunflowersMay 1–May 22
CucumbersMay 15–May 22
CornMay 8–May 22
Sweet potatoesMay 22–Jun 5
WatermelonMay 15–May 29
Green beansMay 8–May 29
ZucchiniMay 8–May 22
OkraMay 22–Jun 5
PeppersMay 15–May 29
BasilMay 8–May 22
Butternut squashMay 8–May 22
CantaloupeMay 15–May 29
EggplantMay 15–May 29
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesApr 3–Apr 17
OnionsMar 20–Apr 10
CarrotsApr 10–May 15
LettuceApr 17–May 8
BroccoliApr 3–Apr 17
BeetsApr 3–May 15
PeasMar 20–Apr 3
CabbageApr 3–Apr 17
RadishesMar 27–May 8
Brussels sproutsApr 17–May 1
SpinachMar 20–Apr 10
CilantroApr 17–May 8
KaleApr 3–Apr 17
Collard greensApr 3–Apr 17
TurnipsApr 3–Apr 17
DillMay 1–May 15
CeleryMay 8–May 15
CauliflowerApr 17–May 1
LeeksApr 17–May 1
Swiss chardApr 17–May 15
ParsleyApr 17–May 8
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsSep 29–Nov 3
GarlicSep 22–Oct 27
Daffodil bulbsSep 15–Oct 27
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesApr 3–Apr 17
AsparagusApr 3–Apr 17

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 18May 1May 18Sep 29Oct 13Oct 25
Hard freeze, 28°FApr 6Apr 19May 5Oct 8Oct 23Nov 6

Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.

Where these numbers come from

NOAA station Waukesha Wwtp (USC00478937) sits 0.3 miles from the center of Waukesha at 789 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.

Questions

When is the last frost in Waukesha, WI?

The average last frost date in Waukesha is May 1, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 18.

When is the first frost in Waukesha?

The first frost in fall usually comes around October 13. One year in ten it arrives before September 29.

How long is the growing season in Waukesha?

About 162 days between the average last and first frost.

When should I plant tomatoes in Waukesha?

Plant tomato seedlings outside from May 8 to May 22. Start seeds indoors six to eight weeks earlier.

Nearby in Wisconsin

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