Interior, SD frost dates
Last spring frostMay 5median date
First fall frostOct 7median date
Growing season155 daysfrost-free
Hardiness zone5aZone 5a
How Interior compares
- In 8 years out of 10, the last spring frost in Interior falls between April 22 and May 20, a 28-day window. The first fall frost falls between September 23 and October 20.
- The median last frost is 1 day earlier than the South Dakota median of May 6.
- Its 155-day growing season is longer than 73% of the 363 South Dakota places with a regular frost season (state median 149 days).
- The last frost is typical for zone 5a, where the median is May 3.
- The weather station records an average of 146 nights a year at or below 32°F.
- Compared with Rapid City, SD, 111 km away, the last frost here is 2 days later than there and the growing season is 3 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 22 |
| 50% (median) | May 5 |
| 10% (safe for tender plants) | May 20 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 23 |
| 50% (median) | October 7 |
| 90% (late) | October 20 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Interior, SD
Interior, SD frost dates — last frost May 5, first frost Oct 7, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 10 to Feb 24Transplant outside: Apr 7 to Apr 21
Start indoors: Feb 24 to Mar 10Transplant outside: May 19 to Jun 2
Start indoors: Feb 24 to Mar 10Transplant outside: May 19 to Jun 2
Start indoors: Mar 10 to Mar 24Transplant outside: May 12 to May 26
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 14 to Apr 28Sow outdoors: Apr 7 to May 12Plant for fall: Aug 12 to Sep 9
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 7 to Apr 21Sow outdoors: Apr 7 to Apr 21Plant for fall: Jul 29 to Aug 19
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 21 to May 5Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 14 to Apr 28Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 21 to May 5Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 24 to Apr 7Transplant outside: May 26 to Jun 9Sow outdoors: May 26 to Jun 9
Start indoors: Mar 24 to Apr 7Transplant outside: May 12 to May 26
Sow outdoors: Mar 24 to Apr 14Plant for fall: Jul 15 to Aug 5
Sow outdoors: Mar 24 to Apr 14Plant for fall: Aug 12 to Sep 2
Sow outdoors: Mar 31 to May 12Plant for fall: Aug 26 to Sep 16
Start indoors: Apr 7 to Apr 14Transplant outside: May 19 to May 26Sow outdoors: May 12 to May 26Plant for fall: Jul 22 to Aug 5
Start indoors: Apr 7 to Apr 14Sow outdoors: May 12 to May 26Plant for fall: Jul 29 to Aug 12
Start indoors: Apr 7 to Apr 14Sow outdoors: May 12 to May 26
Start indoors: Apr 7 to Apr 14Transplant outside: May 19 to Jun 2
Sow outdoors: Apr 14 to May 12Plant for fall: Jul 15 to Jul 29
Sow outdoors: Apr 14 to May 12Plant for fall: Jul 29 to Aug 12
Sow outdoors: Apr 14 to May 5
Sow outdoors: Apr 21 to May 19Plant for fall: Jul 29 to Aug 12
Sow outdoors: Apr 21 to May 12Plant for fall: Aug 12 to Sep 2
Sow outdoors: May 12 to Jun 2Plant for fall: Jul 22 to Aug 5
Sow outdoors: May 12 to May 26
Transplant outside: May 19 to Jun 9
Plant for fall: Sep 23 to Oct 28
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Interior, SD
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 10 – Feb 24 | Apr 7 – Apr 21 | — | — |
| Peppers | Feb 24 – Mar 10 | May 19 – Jun 2 | — | — |
| Eggplant | Feb 24 – Mar 10 | May 19 – Jun 2 | — | — |
| Tomatoes | Mar 10 – Mar 24 | May 12 – May 26 | — | — |
| Lettuce | Mar 10 – Mar 24 | Apr 14 – Apr 28 | Apr 7 – May 12 | Aug 12 – Sep 9 |
| Kale | Mar 10 – Mar 24 | Apr 7 – Apr 21 | Apr 7 – Apr 21 | Jul 29 – Aug 19 |
| Broccoli | Mar 10 – Mar 24 | Apr 21 – May 5 | — | Jul 1 – Jul 22 |
| Cabbage | Mar 10 – Mar 24 | Apr 14 – Apr 28 | — | Jul 1 – Jul 22 |
| Cauliflower | Mar 10 – Mar 24 | Apr 21 – May 5 | — | Jul 1 – Jul 22 |
| Okra | Mar 24 – Apr 7 | May 26 – Jun 9 | May 26 – Jun 9 | — |
| Basil | Mar 24 – Apr 7 | May 12 – May 26 | — | — |
| Peas | — | — | Mar 24 – Apr 14 | Jul 15 – Aug 5 |
| Spinach | — | — | Mar 24 – Apr 14 | Aug 12 – Sep 2 |
| Radishes | — | — | Mar 31 – May 12 | Aug 26 – Sep 16 |
| Cucumbers | Apr 7 – Apr 14 | May 19 – May 26 | May 12 – May 26 | Jul 22 – Aug 5 |
| Zucchini & Summer Squash | Apr 7 – Apr 14 | — | May 12 – May 26 | Jul 29 – Aug 12 |
| Winter Squash & Pumpkins | Apr 7 – Apr 14 | — | May 12 – May 26 | — |
| Melons & Watermelon | Apr 7 – Apr 14 | May 19 – Jun 2 | — | — |
| Carrots | — | — | Apr 14 – May 12 | Jul 15 – Jul 29 |
| Beets | — | — | Apr 14 – May 12 | Jul 29 – Aug 12 |
| Potatoes | — | — | Apr 14 – May 5 | — |
| Swiss Chard | — | — | Apr 21 – May 19 | Jul 29 – Aug 12 |
| Cilantro | — | — | Apr 21 – May 12 | Aug 12 – Sep 2 |
| Green Beans | — | — | May 12 – Jun 2 | Jul 22 – Aug 5 |
| Sweet Corn | — | — | May 12 – May 26 | — |
| Sweet Potatoes | — | May 19 – Jun 9 | — | — |
| Garlic | — | — | — | Sep 23 – Oct 28 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Interior 3 Ne, SD weather station, 3 km away (elevation 2,441 ft (744 m)).
Frost dates near Interior
- Wanblee May 9 · Oct 1
- Wall May 10 · Oct 1
- Kadoka May 11 · Sep 30
- Kyle May 11 · Oct 1
- Quinn May 16 · Sep 26
- Philip May 11 · Sep 30
- Scenic May 10 · Oct 1
- Allen May 13 · Oct 2
- Long Valley May 9 · Oct 1
- Owanka May 10 · Oct 1
Frequently asked questions
When is the last frost in Interior, SD?
The median last spring frost in Interior, SD is May 5. There is still about a 10% chance of frost after May 20, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Interior, SD?
The median first fall frost is October 7, with about a 10% chance of frost before September 23.
How long is the growing season in Interior, SD?
About 155 days between the median last spring frost and first fall frost.
What planting zone is Interior, SD?
Interior, SD is in USDA hardiness zone 5a.