Frost Report

All states Iowa

Frost dates for Osceola, IA

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 29

typical year

Safe to plant

May 11

frost is over in 9 of 10 years

First fall frost

October 9

typical year

Growing season

162 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 1 – 15 –
Spinach – Mar 18 – Apr 8 Aug 14 – 28
Lettuce – Apr 1 – 22 Aug 14 – 28
Radishes – Apr 1 – May 13 Aug 28 – Sep 11
Onions – Apr 1 – 15 –
Potatoes – Apr 8 – 22 –
Carrots – Apr 8 – 29 Jul 17 – 31
Beets – Apr 1 – 15 Jul 31 – Aug 14
Kale Feb 18 – Mar 4 Apr 1 – 15 Jul 31 – Aug 14
Broccoli Feb 18 – Mar 4 Apr 15 – 29 Jul 31 – Aug 14
Cabbage Feb 4 – 18 Apr 1 – 15 Jul 31 – Aug 14
Garlic – – Aug 28 – Sep 18
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 – Jul 31 –
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 29April 13
Fall frost before September 24October 9October 24

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 20.

Towns that use these dates

This is the nearest NOAA station with frost records for 6 towns.

Osceola, Murray, New Virginia, Van Wert, Weldon, Woodburn

Where these dates come from

NOAA weather station OSCEOLA, IA US (USC00136316), 1991–2020 climate normals. It's the nearest station for 5 zip codes, all within 12 miles:

50174, 50213, 50262, 50264, 50275

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