Frost dates for 57701Rapid City, SD
The average last spring frost in Rapid City is May 3 and the average first fall frost is October 8, giving a typical growing season of about 157 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 3
- Average first fall frost
- Oct 8
- Growing season
- 157 days
Safer after May 17 (1-in-10 risk)
Possible by Sep 26 (1-in-10 risk)
Last frost typically in 182 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 1 · May 15 · May 29 | Sep 19 · Oct 1 · Oct 14 | 137 days | 100% |
| Frost / freeze (32°F) | Apr 20 · May 3 · May 17 | Sep 26 · Oct 8 · Oct 23 | 157 days | 100% |
| Hard freeze (28°F) | Apr 8 · Apr 22 · May 5 | Oct 3 · Oct 18 · Nov 1 | 178 days | 100% |
Planting calendar for Rapid 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 | Apr 2 – Jun 8 |
| Tomatoes | Transplant outdoors | May 19 – Jun 18 |
| Peppers | Start seeds indoors | Apr 2 – May 3 |
| Peppers | Transplant outdoors | Jun 2 – Jul 3 |
| Eggplant | Start seeds indoors | Apr 19 – May 18 |
| Eggplant | Transplant outdoors | Jun 2 – Jul 3 |
| Cucumbers | Sow outdoors | Jun 2 – Jun 28 |
| Summer squash | Sow outdoors | May 19 – Jul 3 |
| Winter squash & pumpkins | Sow outdoors | Jun 2 – Jul 3 |
| Snap beans | Sow outdoors | May 19 – Jul 21 |
| Sweet corn | Sow outdoors | May 19 – Jun 18 |
| Watermelon & cantaloupe | Sow outdoors | Jun 2 – Jul 3 |
| Okra | Sow outdoors | May 26 – Jun 18 |
| Peas | Sow outdoors (spring) | Apr 2 – May 18 |
| Potatoes | Plant outdoors (spring) | Apr 2 – Jun 2 |
| Onions | Start seeds indoors (spring) | Feb 19 – Mar 18 |
| Onions | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (spring) | Mar 15 – Apr 18 |
| Broccoli | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (fall) | Jun 8 – Jun 18 |
| Broccoli | Transplant outdoors (fall) | Jul 8 – Jul 19 |
| Cabbage | Start seeds indoors (spring) | Mar 5 – Apr 2 |
| Cabbage | Transplant outdoors (spring) | Apr 2 – May 3 |
| Cabbage | Start seeds indoors (fall) | May 29 – Jun 28 |
| Cabbage | Transplant outdoors (fall) | Jun 28 – Jul 29 |
| Leaf lettuce | Sow outdoors (spring) | Apr 2 – Jun 18 |
| Leaf lettuce | Sow outdoors (fall) | Jun 28 – Aug 14 |
| Spinach | Sow outdoors (spring) | Mar 26 – May 9 |
| Spinach | Sow outdoors (fall) | Jul 15 – Aug 19 |
| Radishes | Sow outdoors (spring) | Apr 2 – May 23 |
| Radishes | Sow outdoors (fall) | Jun 28 – Aug 29 |
| Kale | Sow outdoors (spring) | Apr 19 – May 9 |
| Kale | Sow outdoors (fall) | Jun 21 – Jul 29 |
| Carrots | Sow outdoors (spring) | May 3 – Jun 18 |
| Carrots | Sow outdoors (fall) | May 29 – Jul 14 |
| Garlic | Plant outdoors (fall) | Sep 28 – Oct 29 |
Where these dates come from
ZIP code 57701 is matched to the NOAA station Rapid City Wfo, SD, 7.7 km away, at 3,379 ft elevation (85 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Rapid City Wfo, SD (used) | 3,379 ft | May 3 | Oct 8 |
| Rapid City 4Nw, SD | 3,479 ft | May 10 | Oct 5 |
| Rapid City Rgnl Ap, SD | 3,160 ft | May 12 | Oct 1 |
| Johnson Siding, SD | 4,184 ft | May 20 | Sep 25 |
Frost dates near Rapid City
- Ellsworth Afb, SD 57706 · last May 12, first Oct 1
- Rapid City, SD 57703 · last May 3, first Oct 8
- Box Elder, SD 57719 · last May 12, first Oct 1
- Black Hawk, SD 57718 · last May 20, first Sep 25
- Piedmont, SD 57769 · last May 10, first Oct 5
- Nemo, SD 57759 · last May 28, first Sep 18
- Sturgis, SD 57785 · last May 8, first Oct 3
- New Underwood, SD 57761 · last May 12, first Oct 1
Frequently asked questions
- When is the last frost in Rapid City, SD?
- For ZIP code 57701, the average last spring frost (32°F) is May 3, based on NOAA 1991-2020 climate normals for the Rapid City Wfo, SD weather station. There is a 1-in-10 chance of a frost after May 17.
- When is the first frost in Rapid City, SD?
- The average first fall frost (32°F) is October 8. There is a 1-in-10 chance of frost by September 26, so tender plants are at risk from that point on.
- How long is the growing season in 57701?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 157 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.