When is the last frost in Green Bay, WI?

The average last spring frost (50% probability of 32°F) in Green Bay is around April 30, based on NOAA/NCEI 1991–2020 normals at the Green Bay, WI station (4.8 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 Green Bay?

The average first fall frost in Green Bay, WI is around October 9, giving roughly a 161-day frost-free growing season.

What planting zone is Green Bay, WI?

Green Bay 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 Green Bay?

In Green Bay, WI the warmest month is July (avg high 81°F) and the coldest is January (avg low 11.1°F). It averages about 31.6″ of precipitation a year and 55.6″ of snow.

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Green Bay, WI Planting Calendar & Frost Dates

USDA hardiness zone 5b · ZIP 54301 · elevation 208′ · NOAA & USDA data

Green Bay is in USDA hardiness zone 5b (winters can dip to -15 to -10°F), with a growing season of about 161 days between the average last spring frost (April 30) and first fall frost (October 9). The warmest month is July (avg high 81°F); the coldest is January (avg low 11.1°F). It averages 31.6″ of precipitation a year and 55.6″ 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 9

avg (50% prob, 32°F)

Growing season

161 days

frost-free window

Warmest month

July

avg high 81°F

Month-by-month typical weather in Green Bay

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Green Bay, WI (4.8 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	25.5	11.1	18.3	1.4	14.3
February	29	13.2	21.1	1.2	12
March	40.4	23.9	32.1	2	8.1
April	53.8	34.8	44.3	3	4.7
May	67.1	46	56.5	3.4	0
June	76.6	56.2	66.4	4.1	0
July	81	60.1	70.5	3.6	0
August	78.9	58.2	68.6	3.4	0
September	71.7	50.2	61	3.2	0
October	58	39.5	48.7	2.7	0.3
November	43.5	28.9	36.2	2	3.1
December	31.1	18	24.5	1.8	13.1

What to plant when in Green Bay

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 14
Spinach	cool	Sow (spring): March 19 · Sow (fall): August 14
Lettuce	cool	Sow (spring): April 2 · Sow (fall): August 14
Kale	cool	Transplant (spring): April 9 · Sow (fall): July 31
Broccoli	cool	Transplant (spring): April 16
Carrots	cool	Sow (spring): April 9 · Sow (fall): July 31
Onions	cool	Transplant (spring): April 2
Potatoes	cool	Plant seed potatoes: April 16
Radishes	cool	Sow (spring): April 2 · Sow (fall): August 28

Dates are computed from Green Bay'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.

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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

Appleton, WI Oshkosh, WI Sheboygan, WI Fond Du Lac, WI Wausau, WI Brookfield, WI Milwaukee, WI Waukesha, 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 — Green Bay, WI, 4.8 mi (confidence: high). Monthly weather normals: Green Bay, WI, 4.8 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.