When is the last frost in Des Moines, IA?

The average last spring frost (50% probability of 32°F) in Des Moines is around April 23, based on NOAA/NCEI 1991–2020 normals at the Ankeny, IA station (5.7 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Des Moines?

The average first fall frost in Des Moines, IA is around October 15, giving roughly a 173-day frost-free growing season.

What planting zone is Des Moines, IA?

Des Moines is in USDA plant hardiness zone 5b (average annual extreme minimum temperature -15 to -10°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Des Moines?

In Des Moines, IA the warmest month is July (avg high 85.7°F) and the coldest is January (avg low 11.7°F). It averages about 37.1″ of precipitation a year and 24.7″ of snow.

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Des Moines, IA Planting Calendar & Frost Dates

USDA hardiness zone 5b · ZIP 50307 · elevation 297′ · NOAA & USDA data

Des Moines is in USDA hardiness zone 5b (winters can dip to -15 to -10°F), with a growing season of about 173 days between the average last spring frost (April 23) and first fall frost (October 15). The warmest month is July (avg high 85.7°F); the coldest is January (avg low 11.7°F). It averages 37.1″ of precipitation a year and 24.7″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp -15 to -10°F

Last spring frost

April 23

avg (50% prob, 32°F)

First fall frost

October 15

avg (50% prob, 32°F)

Growing season

173 days

frost-free window

Warmest month

July

avg high 85.7°F

Month-by-month typical weather in Des Moines

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Ankeny, IA (5.7 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	29.5	11.7	20.6	1	6.2
February	34.2	16	25.1	1	8
March	47.4	27.4	37.4	2	3.7
April	61	38.1	49.5	4	0.7
May	71.9	50.3	61.1	5.3	0
June	81.8	60.8	71.3	5.4	0
July	85.7	64.7	75.2	4.2	0
August	83.7	61.7	72.7	4.7	0
September	77.1	52.9	65	3.6	0
October	63.6	40.5	52	2.7	0.6
November	47.8	28.9	38.4	1.9	1
December	34.7	18	26.3	1.4	4.5

What to plant when in Des Moines

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: March 12 · Transplant out: April 30
Peppers	warm	Start seeds indoors: February 26 · Transplant out: May 7
Cucumbers	warm	Direct sow: April 30
Zucchini / squash	warm	Direct sow: April 30
Bush beans	warm	Direct sow: April 30
Sweet corn	warm	Direct sow: April 30
Basil	warm	Transplant out: April 30
Peas	cool	Sow (spring): March 19 · Sow (fall): August 20
Spinach	cool	Sow (spring): March 12 · Sow (fall): August 20
Lettuce	cool	Sow (spring): March 26 · Sow (fall): August 20
Kale	cool	Transplant (spring): April 2 · Sow (fall): August 6
Broccoli	cool	Transplant (spring): April 9
Carrots	cool	Sow (spring): April 2 · Sow (fall): August 6
Onions	cool	Transplant (spring): March 26
Potatoes	cool	Plant seed potatoes: April 9
Radishes	cool	Sow (spring): March 26 · Sow (fall): September 3

Dates are computed from Des Moines's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Iowa

Ankeny, IA Urbandale, IA West Des Moines, IA Ames, IA Waterloo, IA Cedar Falls, IA Cedar Rapids, IA Iowa City, IA

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Ankeny, IA, 5.7 mi (confidence: high). Monthly weather normals: Ankeny, IA, 5.7 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.