Frost dates for 57341Gann Valley, SD
The average last spring frost in Gann Valley is May 6 and the average first fall frost is October 1, giving a typical growing season of about 148 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 6
- Average first fall frost
- Oct 1
- Growing season
- 148 days
Safer after May 19 (1-in-10 risk)
Possible by Sep 20 (1-in-10 risk)
Last frost typically in 185 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | May 3 · May 16 · May 31 | Sep 11 · Sep 24 · Oct 5 | 131 days | 100% |
| Frost / freeze (32°F) | Apr 23 · May 6 · May 19 | Sep 20 · Oct 1 · Oct 13 | 148 days | 100% |
| Hard freeze (28°F) | Apr 13 · Apr 28 · May 9 | Sep 25 · Oct 9 · Oct 24 | 165 days | 100% |
Planting calendar for Gann Valley
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Apr 5 – Jun 11 |
| Tomatoes | Transplant outdoors | May 22 – Jun 11 |
| Peppers | Start seeds indoors | Apr 5 – May 6 |
| Peppers | Transplant outdoors | Jun 5 – Jul 6 |
| Eggplant | Start seeds indoors | Apr 22 – May 21 |
| Eggplant | Transplant outdoors | Jun 5 – Jul 6 |
| Cucumbers | Sow outdoors | Jun 5 – Jun 21 |
| Summer squash | Sow outdoors | May 22 – Jul 6 |
| Winter squash & pumpkins | Sow outdoors | Jun 5 – Jul 6 |
| Snap beans | Sow outdoors | May 22 – Jul 14 |
| Sweet corn | Sow outdoors | May 22 – Jun 11 |
| Watermelon & cantaloupe | Sow outdoors | Jun 5 – Jul 6 |
| Okra | Sow outdoors | May 29 – Jun 21 |
| Peas | Sow outdoors (spring) | Apr 5 – May 21 |
| Potatoes | Plant outdoors (spring) | Apr 5 – Jun 5 |
| Onions | Start seeds indoors (spring) | Feb 22 – Mar 21 |
| Onions | Transplant outdoors (spring) | Apr 22 – May 21 |
| Broccoli | Start seeds indoors (spring) | Mar 18 – Apr 21 |
| Broccoli | Transplant outdoors (spring) | Apr 22 – May 21 |
| Broccoli | Start seeds indoors (fall) | Jun 1 – Jun 11 |
| Broccoli | Transplant outdoors (fall) | Jul 1 – Jul 12 |
| Cabbage | Start seeds indoors (spring) | Mar 8 – Apr 5 |
| Cabbage | Transplant outdoors (spring) | Apr 5 – May 6 |
| Cabbage | Start seeds indoors (fall) | May 22 – Jun 21 |
| Cabbage | Transplant outdoors (fall) | Jun 21 – Jul 22 |
| Leaf lettuce | Sow outdoors (spring) | Apr 5 – Jun 21 |
| Leaf lettuce | Sow outdoors (fall) | Jun 21 – Aug 7 |
| Spinach | Sow outdoors (spring) | Mar 29 – May 12 |
| Spinach | Sow outdoors (fall) | Jul 8 – Aug 12 |
| Radishes | Sow outdoors (spring) | Apr 5 – May 26 |
| Radishes | Sow outdoors (fall) | Jun 21 – Aug 22 |
| Kale | Sow outdoors (spring) | Apr 22 – May 12 |
| Kale | Sow outdoors (fall) | Jun 14 – Jul 22 |
| Carrots | Sow outdoors (spring) | May 6 – Jun 21 |
| Carrots | Sow outdoors (fall) | May 22 – Jul 7 |
| Garlic | Plant outdoors (fall) | Sep 21 – Oct 22 |
Where these dates come from
ZIP code 57341 is matched to the NOAA station Gann Valley 4Nw, SD, 2 km away, at 1,720 ft elevation (97 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Gann Valley 4Nw, SD (used) | 1,720 ft | May 6 | Oct 1 |
| Gann Valley 3 Nne, SD | 1,646 ft | May 7 | Oct 1 |
| Lake Sharpe Prj, SD | 1,461 ft | May 6 | Oct 5 |
| Stephan 2 Nw, SD | 1,805 ft | May 10 | Sep 29 |
Frost dates near Gann Valley
- Fort Thompson, SD 57339 · last May 6, first Oct 5
- Wessington Springs, SD 57382 · last May 2, first Oct 8
- Pukwana, SD 57370 · last May 1, first Oct 7
- Chamberlain, SD 57326 · last May 1, first Oct 7
- Kimball, SD 57355 · last May 3, first Oct 5
- Stephan, SD 57346 · last May 10, first Sep 29
- Oacoma, SD 57365 · last May 1, first Oct 7
- White Lake, SD 57383 · last May 3, first Oct 5
Frequently asked questions
- When is the last frost in Gann Valley, SD?
- For ZIP code 57341, the average last spring frost (32°F) is May 6, based on NOAA 1991-2020 climate normals for the Gann Valley 4Nw, SD weather station. There is a 1-in-10 chance of a frost after May 19.
- When is the first frost in Gann Valley, SD?
- The average first fall frost (32°F) is October 1. There is a 1-in-10 chance of frost by September 20, so tender plants are at risk from that point on.
- How long is the growing season in 57341?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 148 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.