Last frost date in Brookfield, WI

Average last frost
April 30

In Brookfield, the last spring frost comes around April 30 in an average year. Wait until May 15 if you want 90% odds of no more frost. The first fall frost usually arrives about October 14, which leaves 164 frost-free days. An early freeze before September 28 happens one year in ten.

Safe after (10% risk)
May 15
Average first frost
Oct 14
Frost-free season
164 days
Hard freeze (28°F) ends
Apr 19
Next 7 nights in Brookfield

No frost in the next 7 nights

Later than usual: the average first frost here is October 14.

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

  1. ThuOct 2248°
  2. FriOct 2350°
  3. SatOct 2453°
  4. SunOct 2550°
  5. MonOct 2646°
  6. TueOct 2744°
  7. WedOct 2844°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 30First frost Oct 14164 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND164 frost-free days
Frost risk through the year at Brookfield Wwtp, 3.1 miles from Brookfield.

Planting calendar for Brookfield

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 7–May 21
PumpkinsMay 14–May 28
SunflowersApr 30–May 21
CucumbersMay 14–May 21
CornMay 7–May 21
Sweet potatoesMay 21–Jun 4
WatermelonMay 14–May 28
Green beansMay 7–May 28
ZucchiniMay 7–May 21
OkraMay 21–Jun 4
PeppersMay 14–May 28
BasilMay 7–May 21
Butternut squashMay 7–May 21
CantaloupeMay 14–May 28
EggplantMay 14–May 28
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesApr 2–Apr 16
OnionsMar 19–Apr 9
CarrotsApr 9–May 14
LettuceApr 16–May 7
BroccoliApr 2–Apr 16
BeetsApr 2–May 14
PeasMar 19–Apr 2
CabbageApr 2–Apr 16
RadishesMar 26–May 7
Brussels sproutsApr 16–Apr 30
SpinachMar 19–Apr 9
CilantroApr 16–May 7
KaleApr 2–Apr 16
Collard greensApr 2–Apr 16
TurnipsApr 2–Apr 16
DillApr 30–May 14
CeleryMay 7–May 14
CauliflowerApr 16–Apr 30
LeeksApr 16–Apr 30
Swiss chardApr 16–May 14
ParsleyApr 16–May 7
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsSep 30–Nov 4
GarlicSep 23–Oct 28
Daffodil bulbsSep 16–Oct 28
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesApr 2–Apr 16
AsparagusApr 2–Apr 16

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 16Apr 30May 15Sep 28Oct 14Oct 27
Hard freeze, 28°FApr 5Apr 19May 3Oct 10Oct 25Nov 7

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 Brookfield Wwtp (USC00471062) sits 3.1 miles from the center of Brookfield at 830 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 Brookfield, WI?

The average last frost date in Brookfield is April 30, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 15.

When is the first frost in Brookfield?

The first frost in fall usually comes around October 14. One year in ten it arrives before September 28.

How long is the growing season in Brookfield?

About 164 days between the average last and first frost.

When should I plant tomatoes in Brookfield?

Plant tomato seedlings outside from May 7 to May 21. Start seeds indoors six to eight weeks earlier.

Nearby in Wisconsin

All 43 cities in Wisconsin