Frost Report

All states Illinois

Frost dates for Morton, IL

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 21

typical year

Safe to plant

May 7

frost is over in 9 of 10 years

First fall frost

October 17

typical year

Growing season

178 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 24 – Apr 7 –
Spinach – Mar 10 – 31 Aug 22 – Sep 5
Lettuce – Mar 24 – Apr 14 Aug 22 – Sep 5
Radishes – Mar 24 – May 5 Sep 5 – 19
Onions – Mar 24 – Apr 7 –
Potatoes – Mar 31 – Apr 14 –
Carrots – Mar 31 – Apr 21 Jul 25 – Aug 8
Beets – Mar 24 – Apr 7 Aug 8 – 22
Kale Feb 10 – 24 Mar 24 – Apr 7 Aug 8 – 22
Broccoli Feb 10 – 24 Apr 7 – 21 Aug 8 – 22
Cabbage Jan 27 – Feb 10 Mar 24 – Apr 7 Aug 8 – 22
Garlic – – Sep 5 – 26
Warm-season crops
Tomatoes Mar 12 – 26 May 7 – 21 –
Peppers Mar 5 – 19 May 14 – 28 –
Cucumbers – May 7 – 28 –
Zucchini – May 7 – Jun 4 –
Pumpkins – May 7 – 28 –
Green beans – May 7 – Aug 8 –
Sweet corn – May 7 – Jun 4 –
Basil Apr 2 – 16 May 14 – 21 –

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 7April 21April 7
Fall frost before October 3October 17October 30

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 9 (April 27 in a late year), and the first one in fall around October 27.

Towns that use these dates

This is the nearest NOAA station with frost records for 11 towns.

Morton, Washington, Eureka, Metamora, Mackinaw, Goodfield, Hopedale, Deer Creek, Carlock, Congerville, Secor

Where these dates come from

NOAA weather station CONGERVILLE 2NW, IL US (USC00111836), 1991–2020 climate normals. It's the nearest station for 12 zip codes, all within 17 miles:

61530, 61550, 61568, 61571, 61725, 61729, 61732, 61733, 61742, 61747, 61755, 61771

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