Frost Report

All states Wisconsin

Frost dates for Middleton, WI

When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.

Last spring frost

April 28

typical year

Safe to plant

May 11

frost is over in 9 of 10 years

First fall frost

October 15

typical year

Growing season

169 days

frost-free, typical year

When to plant

Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.

CropStart indoorsPlant outsideFall planting
Cool-season crops
Peas – Mar 31 – Apr 14 –
Spinach – Mar 17 – Apr 7 Aug 20 – Sep 3
Lettuce – Mar 31 – Apr 21 Aug 20 – Sep 3
Radishes – Mar 31 – May 12 Sep 3 – 17
Onions – Mar 31 – Apr 14 –
Potatoes – Apr 7 – 21 –
Carrots – Apr 7 – 28 Jul 23 – Aug 6
Beets – Mar 31 – Apr 14 Aug 6 – 20
Kale Feb 17 – Mar 3 Mar 31 – Apr 14 Aug 6 – 20
Broccoli Feb 17 – Mar 3 Apr 14 – 28 Aug 6 – 20
Cabbage Feb 3 – 17 Mar 31 – Apr 14 Aug 6 – 20
Garlic – – Sep 3 – 24
Warm-season crops
Tomatoes Mar 16 – 30 May 11 – 25 –
Peppers Mar 9 – 23 May 18 – Jun 1 –
Cucumbers – May 11 – Jun 1 –
Zucchini – May 11 – Jun 8 –
Pumpkins – May 11 – Jun 1 –
Green beans – May 11 – Aug 6 –
Sweet corn – May 11 – Jun 8 –
Basil Apr 6 – 20 May 18 – 25 –

Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.

The year at a glance

Start indoors Plant outside Fall planting

The chance of frost, by date

1 year in 10Half of years9 years in 10
Spring frost after May 11April 28April 14
Fall frost before September 29October 15October 29

Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.

Hard freeze (28°F)

A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around April 17 (May 1 in a late year), and the first one in fall around October 25.

Towns that use these dates

This is the nearest NOAA station with frost records for 4 towns.

Middleton, Verona, Cross Plains, Shorewood Hills

Where these dates come from

NOAA weather station CHARMANY FARM, WI US (USC00471416), 1991–2020 climate normals. It's the nearest station for 7 zip codes, all within 14 miles:

53508, 53528, 53562, 53593, 53705, 53717, 53719

Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.