When is the last frost in Des Moines, IA?

The average (50% probability) last spring frost in Des Moines is April 18, based on NOAA 1991–2020 normals. A 1-in-10 risk remains until May 2.

When is the first frost in Des Moines?

The average first fall frost in Des Moines is October 20, with a growing season of about 184 days.

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Des Moines, Iowa frost dates

Average last spring frost: April 18. Average first fall frost: October 20. That gives a growing season of about 184 days. For frost-tender plants, a safer planting date is May 2, after which a freeze happens in only 1 year in 10.

Last frost (50%)

Apr 18

1-in-10 risk after May 2

First frost (50%)

Oct 20

1-in-10 risk before Oct 4

Growing season

184 days

median frost-free days

Hard freeze (28°F)

Apr 8

median last 28°F in spring

Frost risk by date

Chance of frost	Spring: frost after	Fall: frost before
90%	April 4	November 1
70%	April 12	October 25
50%	April 18	October 20
30%	April 24	October 14
10%	May 2	October 4

Read the spring column like this: there is a 10% chance of a 32°F freeze after May 2. These are NOAA probabilities for the Des Moines International Airport weather station (USW00014933, elevation 292 m), 1991–2020.

Des Moines vegetable planting calendar

Dates count from the 50% last-frost date (April 18). For tomatoes, peppers and other frost-tender crops, waiting until the 10% date (May 2) is the cautious choice.

Crop	Start seeds indoors	Plant out
Beans	Mar 28	Apr 25 (usually sown directly in the garden)
Broccoli	Feb 7	Mar 21
Brussels sprouts	Feb 7	Mar 21
Cabbage	Jan 31	Mar 14
Cauliflower	Feb 21	Apr 4
Sweet corn	Mar 21	Apr 18 (usually sown directly in the garden)
Cucumbers	Apr 4	Apr 25
Kale	Jan 31	Mar 14
Leeks	Jan 3	Mar 14
Lettuce	Feb 28	Apr 4
Melons	Apr 11	May 2
Onions	Dec 27	Mar 7 (from seed; sets and transplants go out at the same time)
Peas	Feb 21	Mar 21 (usually sown directly in the garden)
Peppers	Mar 7	May 2
Squash	Apr 11	May 2
Tomatoes	Feb 21	Apr 18

Offsets from Oregon State University Extension's seed-starting table. "Plant out" means transplant, or sow directly for crops usually grown from seed.

Fall frost and season extension

The first fall freeze usually arrives around October 20. There's a 1-in-10 chance it comes before October 4. Harvest tender crops such as basil, tomatoes, peppers and squash before then, or cover them on cold nights. Cool-season crops like kale, cabbage and Brussels sprouts handle light frost, and often taste sweeter after it. A hard freeze (28°F) typically comes around October 30.

Nearby cities

City	Last frost (50%)	First frost (50%)	Distance
Cedar Rapids, IA	Apr 27	Oct 11	~166 km
Omaha, NE	Apr 18	Oct 21	~188 km
Kansas City, MO	Apr 13	Oct 24	~264 km
Lincoln, NE	Apr 24	Oct 13	~268 km
Topeka, KS	Apr 12	Oct 23	~319 km
Sioux Falls, SD	May 1	Oct 6	~342 km

More: all Iowa frost dates