When is the last frost in Sioux Falls, SD?

The average last spring frost (50% probability of 32°F) in Sioux Falls is around May 1, based on NOAA/NCEI 1991–2020 normals at the Sioux Falls, SD station (3.9 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 Sioux Falls?

The average first fall frost in Sioux Falls, SD is around October 6, giving roughly a 157-day frost-free growing season.

What planting zone is Sioux Falls, SD?

Sioux Falls is in USDA plant hardiness zone 5a (average annual extreme minimum temperature -20 to -15°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Sioux Falls?

In Sioux Falls, SD the warmest month is July (avg high 85.3°F) and the coldest is January (avg low 8.5°F). It averages about 27.9″ of precipitation a year and 45.3″ of snow.

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Sioux Falls, SD Planting Calendar & Frost Dates

USDA hardiness zone 5a · ZIP 57103 · elevation 436′ · NOAA & USDA data

Sioux Falls is in USDA hardiness zone 5a (winters can dip to -20 to -15°F), with a growing season of about 157 days between the average last spring frost (May 1) and first fall frost (October 6). The warmest month is July (avg high 85.3°F); the coldest is January (avg low 8.5°F). It averages 27.9″ of precipitation a year and 45.3″ 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 -20 to -15°F

Last spring frost

May 1

avg (50% prob, 32°F)

First fall frost

October 6

avg (50% prob, 32°F)

Growing season

157 days

frost-free window

Warmest month

July

avg high 85.3°F

Month-by-month typical weather in Sioux Falls

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Sioux Falls, SD (3.9 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	27.2	8.5	17.9	0.6	8
February	32	12.6	22.3	0.8	8.6
March	45	24.3	34.7	1.6	7.2
April	59	35.5	47.2	3	5.1
May	70.8	47.5	59.1	3.9	0.1
June	80.9	58.8	69.9	4.2	0
July	85.3	63.4	74.4	3.3	0
August	82.8	61.1	72	3.3	0
September	75.6	51.9	63.8	2.7	0
October	61.1	38.1	49.6	2.4	1.4
November	45	24.5	34.8	1.2	6.2
December	31.6	13.4	22.5	0.8	8.7

What to plant when in Sioux Falls

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: March 20 · Transplant out: May 8
Peppers	warm	Start seeds indoors: March 6 · Transplant out: May 15
Cucumbers	warm	Direct sow: May 8
Zucchini / squash	warm	Direct sow: May 8
Bush beans	warm	Direct sow: May 8
Sweet corn	warm	Direct sow: May 8
Basil	warm	Transplant out: May 8
Peas	cool	Sow (spring): March 27 · Sow (fall): August 11
Spinach	cool	Sow (spring): March 20 · Sow (fall): August 11
Lettuce	cool	Sow (spring): April 3 · Sow (fall): August 11
Kale	cool	Transplant (spring): April 10 · Sow (fall): July 28
Broccoli	cool	Transplant (spring): April 17
Carrots	cool	Sow (spring): April 10 · Sow (fall): July 28
Onions	cool	Transplant (spring): April 3
Potatoes	cool	Plant seed potatoes: April 17
Radishes	cool	Sow (spring): April 3 · Sow (fall): August 25

Dates are computed from Sioux Falls'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 South Dakota

Rapid City, SD

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 — Sioux Falls, SD, 3.9 mi (confidence: high). Monthly weather normals: Sioux Falls, SD, 3.9 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.