Frost dates for 57730Custer, SD
The average last spring frost in Custer is May 15 and the average first fall frost is September 29, giving a typical growing season of about 133 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 15
- Average first fall frost
- Sep 29
- Growing season
- 133 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 13 (1-in-10 risk)
Last frost typically in 194 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 15 · May 28 · Jun 12 | Sep 3 · Sep 21 · Oct 2 | 112 days | 100% |
| Frost / freeze (32°F) | May 4 · May 15 · May 30 | Sep 13 · Sep 29 · Oct 11 | 133 days | 100% |
| Hard freeze (28°F) | Apr 22 · May 5 · May 18 | Sep 24 · Oct 6 · Oct 20 | 153 days | 100% |
Planting calendar for Custer
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 14 – Jun 20 |
| Tomatoes | Transplant outdoors | May 31 – Jun 9 |
| Peppers | Start seeds indoors | Apr 14 – May 15 |
| Peppers | Transplant outdoors | Jun 14 – Jul 15 |
| Eggplant | Start seeds indoors | May 1 – May 30 |
| Eggplant | Transplant outdoors | Jun 14 – Jul 15 |
| Cucumbers | Sow outdoors | Jun 14 – Jun 19 |
| Summer squash | Sow outdoors | May 31 – Jul 15 |
| Winter squash & pumpkins | Sow outdoors | Jun 14 – Jul 15 |
| Snap beans | Sow outdoors | May 31 – Jul 12 |
| Sweet corn | Sow outdoors | May 31 – Jun 9 |
| Watermelon & cantaloupe | Sow outdoors | Jun 14 – Jul 15 |
| Okra | Sow outdoors | Jun 7 – Jun 30 |
| Peas | Sow outdoors (spring) | Apr 14 – May 30 |
| Potatoes | Plant outdoors (spring) | Apr 14 – Jun 14 |
| Onions | Start seeds indoors (spring) | Mar 3 – Mar 30 |
| Onions | Transplant outdoors (spring) | May 1 – May 30 |
| Broccoli | Start seeds indoors (spring) | Mar 27 – Apr 30 |
| Broccoli | Transplant outdoors (spring) | May 1 – May 30 |
| Broccoli | Start seeds indoors (fall) | May 30 – Jun 9 |
| Broccoli | Transplant outdoors (fall) | Jun 29 – Jul 10 |
| Cabbage | Start seeds indoors (spring) | Mar 17 – Apr 14 |
| Cabbage | Transplant outdoors (spring) | Apr 14 – May 15 |
| Cabbage | Start seeds indoors (fall) | May 20 – Jun 19 |
| Cabbage | Transplant outdoors (fall) | Jun 19 – Jul 20 |
| Leaf lettuce | Sow outdoors (spring) | Apr 14 – Jun 30 |
| Leaf lettuce | Sow outdoors (fall) | Jun 19 – Aug 5 |
| Spinach | Sow outdoors (spring) | Apr 7 – May 21 |
| Spinach | Sow outdoors (fall) | Jul 6 – Aug 10 |
| Radishes | Sow outdoors (spring) | Apr 14 – Jun 4 |
| Radishes | Sow outdoors (fall) | Jun 19 – Aug 20 |
| Kale | Sow outdoors (spring) | May 1 – May 21 |
| Kale | Sow outdoors (fall) | Jun 12 – Jul 20 |
| Carrots | Sow outdoors (spring) | May 15 – Jun 30 |
| Carrots | Sow outdoors (fall) | May 20 – Jul 5 |
| Garlic | Plant outdoors (fall) | Sep 19 – Oct 20 |
Where these dates come from
ZIP code 57730 is matched to the NOAA station Wind Cave, SD, 12.1 km away, at 4,155 ft elevation (284 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wind Cave, SD (used) | 4,155 ft | May 15 | Sep 29 |
| Custer Co Ap, SD | 5,545 ft | May 23 | Sep 24 |
| Custer, SD | 5,480 ft | May 18 | Sep 28 |
| Mt Rushmore Nmem, SD | 5,311 ft | May 15 | Oct 1 |
Frost dates near Custer
- Pringle, SD 57773 · last Jun 1, first Sep 10
- Fairburn, SD 57738 · last May 16, first Sep 27
- Buffalo Gap, SD 57722 · last May 15, first Sep 27
- Hermosa, SD 57744 · last May 3, first Oct 8
- Keystone, SD 57751 · last May 28, first Sep 18
- Hot Springs, SD 57747 · last May 16, first Sep 27
- Hill City, SD 57745 · last Jun 1, first Sep 10
- Oral, SD 57766 · last May 15, first Sep 27
Frequently asked questions
- When is the last frost in Custer, SD?
- For ZIP code 57730, the average last spring frost (32°F) is May 15, based on NOAA 1991-2020 climate normals for the Wind Cave, SD weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in Custer, SD?
- The average first fall frost (32°F) is September 29. There is a 1-in-10 chance of frost by September 13, so tender plants are at risk from that point on.
- How long is the growing season in 57730?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 133 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.