Frost dates for 57745Hill City, SD
The average last spring frost in Hill City is June 1 and the average first fall frost is September 10, giving a typical growing season of about 102 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 1
- Average first fall frost
- Sep 10
- Growing season
- 102 days
Safer after Jun 19 (1-in-10 risk)
Possible by Aug 29 (1-in-10 risk)
Last frost typically in 211 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 31 · Jun 18 · Jul 7 | Aug 12 · Sep 1 · Sep 14 | 73 days | 100% |
| Frost / freeze (32°F) | May 18 · Jun 1 · Jun 19 | Aug 29 · Sep 10 · Sep 26 | 102 days | 100% |
| Hard freeze (28°F) | May 6 · May 18 · Jun 1 | Sep 6 · Sep 21 · Oct 6 | 126 days | 100% |
Planting calendar for Hill City
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 | May 1 – Jul 7 |
| Tomatoes | Transplant outdoors | Jun 17 – May 21 |
| Peppers | Start seeds indoors | May 1 – Jun 1 |
| Peppers | Transplant outdoors | Jul 1 – Aug 1 |
| Eggplant | Start seeds indoors | May 18 – Jun 16 |
| Eggplant | Transplant outdoors | Jul 1 – Aug 1 |
| Cucumbers | Sow outdoors | Jul 1 – May 31 |
| Summer squash | Sow outdoors | Jun 17 – Aug 1 |
| Winter squash & pumpkins | Sow outdoors | Jul 1 – Aug 1 |
| Snap beans | Sow outdoors | Jun 17 – Jun 23 |
| Sweet corn | Sow outdoors | Jun 17 – May 21 |
| Watermelon & cantaloupe | Sow outdoors | Jul 1 – Aug 1 |
| Okra | Sow outdoors | Jun 24 – Jul 17 |
| Peas | Sow outdoors (spring) | May 1 – Jun 16 |
| Potatoes | Plant outdoors (spring) | May 1 – Jul 1 |
| Onions | Start seeds indoors (spring) | Mar 20 – Apr 16 |
| Onions | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (spring) | Apr 13 – May 17 |
| Broccoli | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (fall) | May 11 – May 21 |
| Broccoli | Transplant outdoors (fall) | Jun 10 – Jun 21 |
| Cabbage | Start seeds indoors (spring) | Apr 3 – May 1 |
| Cabbage | Transplant outdoors (spring) | May 1 – Jun 1 |
| Cabbage | Start seeds indoors (fall) | May 1 – May 31 |
| Cabbage | Transplant outdoors (fall) | May 31 – Jul 1 |
| Leaf lettuce | Sow outdoors (spring) | May 1 – Jul 17 |
| Leaf lettuce | Sow outdoors (fall) | May 31 – Jul 17 |
| Spinach | Sow outdoors (spring) | Apr 24 – Jun 7 |
| Spinach | Sow outdoors (fall) | Jun 17 – Jul 22 |
| Radishes | Sow outdoors (spring) | May 1 – Jun 21 |
| Radishes | Sow outdoors (fall) | May 31 – Aug 1 |
| Kale | Sow outdoors (spring) | May 18 – Jun 7 |
| Kale | Sow outdoors (fall) | May 24 – Jul 1 |
| Carrots | Sow outdoors (spring) | Jun 1 – Jul 17 |
| Carrots | Sow outdoors (fall) | May 1 – Jun 16 |
| Garlic | Plant outdoors (fall) | Aug 31 – Oct 1 |
Where these dates come from
ZIP code 57745 is matched to the NOAA station Hill City, SD, 1.7 km away, at 4,946 ft elevation (120 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hill City, SD (used) | 4,946 ft | Jun 1 | Sep 10 |
| Mt Rushmore Nmem, SD | 5,311 ft | May 15 | Oct 1 |
| Pactola Dam, SD | 4,720 ft | May 28 | Sep 18 |
| Custer, SD | 5,480 ft | May 18 | Sep 28 |
Frost dates near Hill City
- Keystone, SD 57751 · last May 28, first Sep 18
- Rapid City, SD 57702 · last May 20, first Sep 25
- Black Hawk, SD 57718 · last May 20, first Sep 25
- Nemo, SD 57759 · last May 28, first Sep 18
- Hermosa, SD 57744 · last May 3, first Oct 8
- Custer, SD 57730 · last May 15, first Sep 29
- Piedmont, SD 57769 · last May 10, first Oct 5
- Pringle, SD 57773 · last Jun 1, first Sep 10
Frequently asked questions
- When is the last frost in Hill City, SD?
- For ZIP code 57745, the average last spring frost (32°F) is June 1, based on NOAA 1991-2020 climate normals for the Hill City, SD weather station. There is a 1-in-10 chance of a frost after June 19.
- When is the first frost in Hill City, SD?
- The average first fall frost (32°F) is September 10. There is a 1-in-10 chance of frost by August 29, so tender plants are at risk from that point on.
- How long is the growing season in 57745?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 102 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.