Frost Report

All states Wisconsin

Frost dates for Oshkosh Wittman, 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 30

typical year

Safe to plant

May 13

frost is over in 9 of 10 years

First fall frost

October 13

typical year

Growing season

165 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 – Apr 2 – 16 –
Spinach – Mar 19 – Apr 9 Aug 18 – Sep 1
Lettuce – Apr 2 – 23 Aug 18 – Sep 1
Radishes – Apr 2 – May 14 Sep 1 – 15
Onions – Apr 2 – 16 –
Potatoes – Apr 9 – 23 –
Carrots – Apr 9 – 30 Jul 21 – Aug 4
Beets – Apr 2 – 16 Aug 4 – 18
Kale Feb 19 – Mar 5 Apr 2 – 16 Aug 4 – 18
Broccoli Feb 19 – Mar 5 Apr 16 – 30 Aug 4 – 18
Cabbage Feb 5 – 19 Apr 2 – 16 Aug 4 – 18
Garlic – – Sep 1 – 22
Warm-season crops
Tomatoes Mar 18 – Apr 1 May 13 – 27 –
Peppers Mar 11 – 25 May 20 – Jun 3 –
Cucumbers – May 13 – Jun 3 –
Zucchini – May 13 – Jun 10 –
Pumpkins – May 13 – Jun 3 –
Green beans – May 13 – Aug 4 –
Sweet corn – May 13 – Jun 10 –
Basil Apr 8 – 22 May 20 – 27 –

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 13April 30April 15
Fall frost before September 29October 13October 28

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 18 (May 2 in a late year), and the first one in fall around October 26.

Where these dates come from

NOAA weather station OSHKOSH WITTMAN AP, WI US (USW00094855), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 3 miles:

54902

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