Frost Report

All states Iowa

Frost dates for Mondamin, 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

May 1

typical year

Safe to plant

May 12

frost is over in 9 of 10 years

First fall frost

October 3

typical year

Growing season

155 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 3 – 17 –
Spinach – Mar 20 – Apr 10 Aug 8 – 22
Lettuce – Apr 3 – 24 Aug 8 – 22
Radishes – Apr 3 – May 15 Aug 22 – Sep 5
Onions – Apr 3 – 17 –
Potatoes – Apr 10 – 24 –
Carrots – Apr 10 – May 1 Jul 11 – 25
Beets – Apr 3 – 17 Jul 25 – Aug 8
Kale Feb 20 – Mar 6 Apr 3 – 17 Jul 25 – Aug 8
Broccoli Feb 20 – Mar 6 Apr 17 – May 1 Jul 25 – Aug 8
Cabbage Feb 6 – 20 Apr 3 – 17 Jul 25 – Aug 8
Garlic – – Aug 22 – Sep 12
Warm-season crops
Tomatoes Mar 17 – 31 May 12 – 26 –
Peppers Mar 10 – 24 May 19 – Jun 2 –
Cucumbers – May 12 – Jun 2 –
Zucchini – May 12 – Jun 9 –
Pumpkins – May 12 – Jun 2 –
Green beans – May 12 – Jul 25 –
Sweet corn – May 12 – Jun 9 –
Basil Apr 7 – 21 May 19 – 26 –

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 12May 1April 17
Fall frost before September 20October 3October 17

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 22 (May 4 in a late year), and the first one in fall around October 14.

Towns that use these dates

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

Mondamin, Pisgah, Blencoe, Little Sioux

Where these dates come from

NOAA weather station LITTLE SIOUX 2 NW, IA US (USC00134874), 1991–2020 climate normals. It's the nearest station for 4 zip codes, all within 7 miles:

51523, 51545, 51557, 51564

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