Frost dates for 57717Belle Fourche, SD
The average last spring frost in Belle Fourche is May 10 and the average first fall frost is September 30, giving a typical growing season of about 143 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 10
- Average first fall frost
- Sep 30
- Growing season
- 143 days
Safer after May 25 (1-in-10 risk)
Possible by Sep 16 (1-in-10 risk)
Last frost typically in 189 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 8 · May 21 · Jun 4 | Sep 8 · Sep 21 · Oct 4 | 122 days | 100% |
| Frost / freeze (32°F) | Apr 27 · May 10 · May 25 | Sep 16 · Sep 30 · Oct 13 | 143 days | 100% |
| Hard freeze (28°F) | Apr 14 · Apr 30 · May 15 | Sep 23 · Oct 10 · Oct 24 | 163 days | 100% |
Planting calendar for Belle Fourche
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 9 – Jun 15 |
| Tomatoes | Transplant outdoors | May 26 – Jun 10 |
| Peppers | Start seeds indoors | Apr 9 – May 10 |
| Peppers | Transplant outdoors | Jun 9 – Jul 10 |
| Eggplant | Start seeds indoors | Apr 26 – May 25 |
| Eggplant | Transplant outdoors | Jun 9 – Jul 10 |
| Cucumbers | Sow outdoors | Jun 9 – Jun 20 |
| Summer squash | Sow outdoors | May 26 – Jul 10 |
| Winter squash & pumpkins | Sow outdoors | Jun 9 – Jul 10 |
| Snap beans | Sow outdoors | May 26 – Jul 13 |
| Sweet corn | Sow outdoors | May 26 – Jun 10 |
| Watermelon & cantaloupe | Sow outdoors | Jun 9 – Jul 10 |
| Okra | Sow outdoors | Jun 2 – Jun 25 |
| Peas | Sow outdoors (spring) | Apr 9 – May 25 |
| Potatoes | Plant outdoors (spring) | Apr 9 – Jun 9 |
| Onions | Start seeds indoors (spring) | Feb 26 – Mar 25 |
| Onions | Transplant outdoors (spring) | Apr 26 – May 25 |
| Broccoli | Start seeds indoors (spring) | Mar 22 – Apr 25 |
| Broccoli | Transplant outdoors (spring) | Apr 26 – May 25 |
| Broccoli | Start seeds indoors (fall) | May 31 – Jun 10 |
| Broccoli | Transplant outdoors (fall) | Jun 30 – Jul 11 |
| Cabbage | Start seeds indoors (spring) | Mar 12 – Apr 9 |
| Cabbage | Transplant outdoors (spring) | Apr 9 – May 10 |
| Cabbage | Start seeds indoors (fall) | May 21 – Jun 20 |
| Cabbage | Transplant outdoors (fall) | Jun 20 – Jul 21 |
| Leaf lettuce | Sow outdoors (spring) | Apr 9 – Jun 25 |
| Leaf lettuce | Sow outdoors (fall) | Jun 20 – Aug 6 |
| Spinach | Sow outdoors (spring) | Apr 2 – May 16 |
| Spinach | Sow outdoors (fall) | Jul 7 – Aug 11 |
| Radishes | Sow outdoors (spring) | Apr 9 – May 30 |
| Radishes | Sow outdoors (fall) | Jun 20 – Aug 21 |
| Kale | Sow outdoors (spring) | Apr 26 – May 16 |
| Kale | Sow outdoors (fall) | Jun 13 – Jul 21 |
| Carrots | Sow outdoors (spring) | May 10 – Jun 25 |
| Carrots | Sow outdoors (fall) | May 21 – Jul 6 |
| Garlic | Plant outdoors (fall) | Sep 20 – Oct 21 |
Where these dates come from
ZIP code 57717 is matched to the NOAA station Belle Fourche, SD, 0.9 km away, at 3,020 ft elevation (11 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Belle Fourche, SD (used) | 3,020 ft | May 10 | Sep 30 |
| Spearfish, SD | 3,633 ft | May 12 | Oct 2 |
| Bear Ridge, SD | 3,900 ft | May 17 | Sep 27 |
| Newell, SD | 2,860 ft | May 8 | Oct 1 |
Frost dates near Belle Fourche
- Saint Onge, SD 57779 · last May 12, first Oct 2
- Spearfish, SD 57799 · last May 12, first Oct 2
- Beulah, WY 82712 · last May 12, first Oct 2
- Nisland, SD 57762 · last May 8, first Oct 1
- Whitewood, SD 57793 · last May 12, first Oct 2
- Aladdin, WY 82710 · last May 7, first Oct 3
- Deadwood, SD 57732 · last May 24, first Sep 25
- Newell, SD 57760 · last May 8, first Oct 1
Frequently asked questions
- When is the last frost in Belle Fourche, SD?
- For ZIP code 57717, the average last spring frost (32°F) is May 10, based on NOAA 1991-2020 climate normals for the Belle Fourche, SD weather station. There is a 1-in-10 chance of a frost after May 25.
- When is the first frost in Belle Fourche, SD?
- The average first fall frost (32°F) is September 30. There is a 1-in-10 chance of frost by September 16, so tender plants are at risk from that point on.
- How long is the growing season in 57717?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 143 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.