When is the last frost in Waukesha, WI?

The average last spring frost (50% probability of 32°F) in Waukesha is around April 30, based on NOAA/NCEI 1991–2020 normals at the Brookfield Wwtp, WI station (2.5 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Waukesha?

The average first fall frost in Waukesha, WI is around October 14, giving roughly a 164-day frost-free growing season.

What planting zone is Waukesha, WI?

Waukesha is in USDA plant hardiness zone 5b (average annual extreme minimum temperature -15 to -10°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Waukesha?

In Waukesha, WI the warmest month is July (avg high 81.4°F) and the coldest is January (avg low 11.6°F). It averages about 36″ of precipitation a year and 36.9″ of snow.

Home › Wisconsin › Waukesha

Waukesha, WI Planting Calendar & Frost Dates

USDA hardiness zone 5b · ZIP 53186 · elevation 241′ · NOAA & USDA data

Waukesha is in USDA hardiness zone 5b (winters can dip to -15 to -10°F), with a growing season of about 164 days between the average last spring frost (April 30) and first fall frost (October 14). The warmest month is July (avg high 81.4°F); the coldest is January (avg low 11.6°F). It averages 36″ of precipitation a year and 36.9″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp -15 to -10°F

Last spring frost

April 30

avg (50% prob, 32°F)

First fall frost

October 14

avg (50% prob, 32°F)

Growing season

164 days

frost-free window

Warmest month

July

avg high 81.4°F

Month-by-month typical weather in Waukesha

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Waukesha Wwtp, WI (2.5 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	27.7	11.6	19.7	1.6	10.4
February	31.5	14.6	23	1.7	10.1
March	43	24	33.5	1.9	4.6
April	55.3	34.8	45.1	3.7	1.1
May	67.3	45.8	56.6	4	0
June	77.4	55.6	66.5	4.9	0
July	81.4	60.3	70.9	4	0
August	79.8	58.9	69.4	4.2	0
September	72.9	51.1	62	3.3	0
October	60	39.8	49.9	2.9	0.1
November	45	28.3	36.7	2.2	1.8
December	33	18.1	25.5	1.7	8.8

What to plant when in Waukesha

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: March 19 · Transplant out: May 7
Peppers	warm	Start seeds indoors: March 5 · Transplant out: May 14
Cucumbers	warm	Direct sow: May 7
Zucchini / squash	warm	Direct sow: May 7
Bush beans	warm	Direct sow: May 7
Sweet corn	warm	Direct sow: May 7
Basil	warm	Transplant out: May 7
Peas	cool	Sow (spring): March 26 · Sow (fall): August 19
Spinach	cool	Sow (spring): March 19 · Sow (fall): August 19
Lettuce	cool	Sow (spring): April 2 · Sow (fall): August 19
Kale	cool	Transplant (spring): April 9 · Sow (fall): August 5
Broccoli	cool	Transplant (spring): April 16
Carrots	cool	Sow (spring): April 9 · Sow (fall): August 5
Onions	cool	Transplant (spring): April 2
Potatoes	cool	Plant seed potatoes: April 16
Radishes	cool	Sow (spring): April 2 · Sow (fall): September 2

Dates are computed from Waukesha's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

Want the exact dates for your yard? →
Look up your precise ZIP-code frost dates and a full 26-crop planting calendar on our free interactive tool.
Open the frost & planting tool

🌾 Get a frost reminder

One email in early spring and early fall with the dates for your area. No spam.

Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Wisconsin

New Berlin, WI Brookfield, WI Milwaukee, WI Racine, WI Kenosha, WI Janesville, WI Fond Du Lac, WI Beloit, WI

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Brookfield Wwtp, WI, 2.5 mi (confidence: high). Monthly weather normals: Waukesha Wwtp, WI, 2.5 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.