Sioux Falls, South Dakota: planting zone & frost dates
Sioux Falls is in USDA plant hardiness zone 5a, where the average coldest winter night reaches -20 to -15°F (-28.9 to -26.1°C). The typical last spring frost is around May 6 and the first fall frost around Sep 30.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 14 | Sep 23 |
| Typical planning date (30% risk) | May 6 | Sep 30 |
| Median (50%) | May 1 | Oct 6 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station SIOUX FALLS, SD (USW00014944), 3.2 mi (5.2 km) from the city center and 46 ft lower than the city center (-14 m). Record used for the 1991–2020 normals: 29 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Sioux Falls
All 8 ZIP codes covering Sioux Falls are in zone 5a.
Vegetable planting calendar for Sioux Falls
Dates are counted from the 30%-risk frost dates above (last frost May 6, first frost Sep 30). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 11 – Mar 25 | May 13 – May 27 | — | — |
| Pepper | Feb 25 – Mar 11 | May 20 – Jun 3 | — | — |
| Lettuce | Mar 25 – Apr 8 | Apr 22 – May 13 | Apr 8 – May 20 | Jul 22 – Aug 19 |
| Green Beans | — | — | May 13 – Jun 17 | Jul 8 – Jul 22 |
| Sweet Corn | — | — | May 13 – Jun 10 | — |
| Zucchini & Summer Squash | Apr 8 – Apr 15 | May 13 – May 27 | May 13 – Jun 3 | Jul 8 – Jul 22 |
| Cucumber | Apr 8 – Apr 15 | May 20 – May 27 | May 13 – Jun 3 | Jul 8 – Jul 22 |
| Carrot | — | — | Apr 15 – May 20 | Jul 8 – Jul 22 |
| Onion | Feb 11 – Feb 25 | Apr 8 – Apr 22 | — | — |
| Potato | — | Apr 8 – Apr 29 | — | — |
| Basil | Mar 25 – Apr 8 | May 20 – Jun 3 | May 20 – Jun 10 | — |
| Spinach | — | — | Mar 25 – Apr 22 | Aug 5 – Sep 2 |
| Kale | Mar 11 – Mar 25 | Apr 8 – Apr 29 | Apr 8 – Apr 29 | Jul 22 – Aug 19 |
| Broccoli | Mar 11 – Mar 25 | Apr 22 – May 13 | — | Jul 8 – Jul 22 |
| Peas | — | — | Mar 25 – Apr 15 | Jul 22 – Aug 5 |
| Eggplant | Feb 25 – Mar 11 | May 20 – Jun 3 | — | — |
| Cabbage | Mar 11 – Mar 25 | Apr 8 – Apr 22 | — | Jul 8 – Jul 22 |
| Radish | — | — | Apr 1 – May 20 | Aug 19 – Sep 16 |
| Strawberry | — | Apr 8 – Apr 29 | — | — |
| Beets | — | — | Apr 15 – May 27 | Jul 22 – Aug 5 |
Nearby cities in South Dakota
- Rapid City — zone 5a, last frost May 9, first frost Oct 1
More: all South Dakota cities · other zone 5a cities: Minneapolis, MN, St. Paul, MN, Anchorage, AK, Cedar Rapids, IA, Billings, MT, Bloomington, MN, Sioux City, IA, Brooklyn Park, MN
Sioux Falls gardening questions
When is the last frost in Sioux Falls, SD?
Plan around May 6. At NOAA's Sioux Falls, SD station, 3.2 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by May 1, and after May 14 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 22. The last frost is fairly predictable here: only 26 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Sioux Falls, SD?
Start seeds indoors Mar 11 – Mar 25 and set transplants outside May 13 – May 27, once nights stay above 50°F and the soil is near 60°F. That leaves 147 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Sioux Falls?
About 157 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 138 days, and in 1 year in 10 it runs 176 days or more. In fall there is a 10% chance of frost by Sep 23 and a 30% chance by Sep 30.
When should I plant a fall garden in Sioux Falls?
Count back from the first fall frost (Sep 30): transplant broccoli Jul 8 – Jul 22; sow kale Jul 22 – Aug 19; sow lettuce Jul 22 – Aug 19; sow radishes Aug 19 – Sep 16. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 17. How the math works: succession and fall planting.
Did Sioux Falls's hardiness zone change on the 2023 map?
Yes. Most of Sioux Falls was zone 4b on the 2012 map and is zone 5a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Sioux Falls compare with Sioux City, IA?
Both are in zone 5a. The typical last spring frost in Sioux Falls (May 6) comes about the same time as in Sioux City, IA (May 4), 74 miles away, and the first fall frost is Sep 30 versus Oct 1. Sioux Falls sits about 388 ft higher, which explains part of the gap. The two cities use different NOAA stations.