Trail City, SD frost dates
Last spring frostMay 3median date
First fall frostOct 8median date
Growing season158 daysfrost-free
Hardiness zone4bZone 4b
How Trail City compares
- In 8 years out of 10, the last spring frost in Trail City falls between April 20 and May 16, a 26-day window. The first fall frost falls between September 25 and October 21.
- The median last frost is 3 days earlier than the South Dakota median of May 6.
- Its 158-day growing season is longer than 82% of the 363 South Dakota places with a regular frost season (state median 149 days).
- The last frost is 5 days earlier than the zone 4b median of May 8. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4b chart.
- The weather station records an average of 169 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 20 |
| 50% (median) | May 3 |
| 10% (safe for tender plants) | May 16 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 25 |
| 50% (median) | October 8 |
| 90% (late) | October 21 |
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 Trail City, SD
Trail City, SD frost dates — last frost May 3, first frost Oct 8, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Feb 8 to Feb 22Transplant outside: Apr 5 to Apr 19
Start indoors: Feb 22 to Mar 8Transplant outside: May 17 to May 31
Start indoors: Feb 22 to Mar 8Transplant outside: May 17 to May 31
Start indoors: Mar 8 to Mar 22Transplant outside: May 10 to May 24
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 12 to Apr 26Sow outdoors: Apr 5 to May 10Plant for fall: Aug 13 to Sep 10
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 5 to Apr 19Sow outdoors: Apr 5 to Apr 19Plant for fall: Jul 30 to Aug 20
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 19 to May 3Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 12 to Apr 26Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 19 to May 3Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 22 to Apr 5Transplant outside: May 24 to Jun 7Sow outdoors: May 24 to Jun 7
Start indoors: Mar 22 to Apr 5Transplant outside: May 10 to May 24
Sow outdoors: Mar 22 to Apr 12Plant for fall: Jul 16 to Aug 6
Sow outdoors: Mar 22 to Apr 12Plant for fall: Aug 13 to Sep 3
Sow outdoors: Mar 29 to May 10Plant for fall: Aug 27 to Sep 17
Start indoors: Apr 5 to Apr 12Transplant outside: May 17 to May 24Sow outdoors: May 10 to May 24Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 5 to Apr 12Sow outdoors: May 10 to May 24Plant for fall: Jul 30 to Aug 13
Start indoors: Apr 5 to Apr 12Sow outdoors: May 10 to May 24
Start indoors: Apr 5 to Apr 12Transplant outside: May 17 to May 31
Sow outdoors: Apr 12 to May 10Plant for fall: Jul 16 to Jul 30
Sow outdoors: Apr 12 to May 10Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 12 to May 3
Sow outdoors: Apr 19 to May 17Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 19 to May 10Plant for fall: Aug 13 to Sep 3
Sow outdoors: May 10 to May 31Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 10 to May 24
Transplant outside: May 17 to Jun 7
Plant for fall: Sep 24 to Oct 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Trail City, SD
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 8 – Feb 22 | Apr 5 – Apr 19 | — | — |
| Peppers | Feb 22 – Mar 8 | May 17 – May 31 | — | — |
| Eggplant | Feb 22 – Mar 8 | May 17 – May 31 | — | — |
| Tomatoes | Mar 8 – Mar 22 | May 10 – May 24 | — | — |
| Lettuce | Mar 8 – Mar 22 | Apr 12 – Apr 26 | Apr 5 – May 10 | Aug 13 – Sep 10 |
| Kale | Mar 8 – Mar 22 | Apr 5 – Apr 19 | Apr 5 – Apr 19 | Jul 30 – Aug 20 |
| Broccoli | Mar 8 – Mar 22 | Apr 19 – May 3 | — | Jul 2 – Jul 23 |
| Cabbage | Mar 8 – Mar 22 | Apr 12 – Apr 26 | — | Jul 2 – Jul 23 |
| Cauliflower | Mar 8 – Mar 22 | Apr 19 – May 3 | — | Jul 2 – Jul 23 |
| Okra | Mar 22 – Apr 5 | May 24 – Jun 7 | May 24 – Jun 7 | — |
| Basil | Mar 22 – Apr 5 | May 10 – May 24 | — | — |
| Peas | — | — | Mar 22 – Apr 12 | Jul 16 – Aug 6 |
| Spinach | — | — | Mar 22 – Apr 12 | Aug 13 – Sep 3 |
| Radishes | — | — | Mar 29 – May 10 | Aug 27 – Sep 17 |
| Cucumbers | Apr 5 – Apr 12 | May 17 – May 24 | May 10 – May 24 | Jul 23 – Aug 6 |
| Zucchini & Summer Squash | Apr 5 – Apr 12 | — | May 10 – May 24 | Jul 30 – Aug 13 |
| Winter Squash & Pumpkins | Apr 5 – Apr 12 | — | May 10 – May 24 | — |
| Melons & Watermelon | Apr 5 – Apr 12 | May 17 – May 31 | — | — |
| Carrots | — | — | Apr 12 – May 10 | Jul 16 – Jul 30 |
| Beets | — | — | Apr 12 – May 10 | Jul 30 – Aug 13 |
| Potatoes | — | — | Apr 12 – May 3 | — |
| Swiss Chard | — | — | Apr 19 – May 17 | Jul 30 – Aug 13 |
| Cilantro | — | — | Apr 19 – May 10 | Aug 13 – Sep 3 |
| Green Beans | — | — | May 10 – May 31 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 10 – May 24 | — |
| Sweet Potatoes | — | May 17 – Jun 7 | — | — |
| Garlic | — | — | — | Sep 24 – Oct 29 |
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 Mobridge 2nnw, SD weather station, 24 km away (elevation 1,693 ft (516 m)).
Frost dates near Trail City
- Glencross May 10 · Sep 30
- Little Eagle May 12 · Sep 28
- Mobridge May 5 · Oct 4
- Timber Lake May 10 · Sep 30
- Whitehorse May 10 · Sep 30
- Wakpala May 3 · Oct 8
- Ridgeview May 5 · Oct 4
- Glenham May 5 · Oct 4
- Mc Intosh May 9 · Sep 30
- Bullhead May 9 · Sep 30
Frequently asked questions
When is the last frost in Trail City, SD?
The median last spring frost in Trail City, SD is May 3. There is still about a 10% chance of frost after May 16, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Trail City, SD?
The median first fall frost is October 8, with about a 10% chance of frost before September 25.
How long is the growing season in Trail City, SD?
About 158 days between the median last spring frost and first fall frost.
What planting zone is Trail City, SD?
Trail City, SD is in USDA hardiness zone 4b.