Rapid City, SD planting zone & frost dates
Rapid City is in USDA hardiness zone 5b. The last spring frost usually comes around May 3 and the first fall frost around October 8, for a growing season of about 157 days.
Planting calendar for Rapid City
Dates are counted from the average last spring frost (May 3) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Mar 8 – Mar 22 Transplant outdoors: May 10 – May 17 |
| Peppers | Start seeds indoors: Feb 22 – Mar 8 Transplant outdoors: May 17 – May 24 |
| Eggplant | Start seeds indoors: Feb 22 – Mar 8 Transplant outdoors: May 17 – May 24 |
| Broccoli | Start seeds indoors: Feb 22 – Mar 8 Transplant outdoors: Apr 5 – Apr 19 |
| Cabbage | Start seeds indoors: Feb 22 – Mar 8 Transplant outdoors: Apr 5 – Apr 19 |
| Onions (sets) | Plant outdoors: Apr 5 – Apr 19 |
| Peas | Sow outdoors: Mar 22 – Apr 5 |
| Spinach | Sow outdoors: Mar 22 – Apr 5 |
| Lettuce | Sow outdoors: Apr 5 – Apr 19 |
| Carrots | Sow outdoors: Apr 5 – Apr 19 |
| Potatoes | Plant outdoors: Apr 5 – Apr 19 |
| Beans | Sow outdoors: May 10 – May 17 |
| Sweet corn | Sow outdoors: May 10 – May 17 |
| Cucumbers | Sow outdoors: May 10 – May 17 |
| Squash & zucchini | Sow outdoors: May 10 – May 17 |
| Basil | Start seeds indoors: Mar 22 – Apr 5 Transplant outdoors: May 10 – May 17 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 13 (8 weeks before the average first fall frost on Oct 8).
Useful for zone 5b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 20 | May 3 | May 17 |
| First 32°F frost in fall is before | Oct 23 | Oct 8 | Sep 26 |
How to read it: in spring there is a 10% chance of a frost after May 17, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 26. A hard freeze (28°F) usually ends around April 22.
Hardiness zone by ZIP code in Rapid City
- 57701 zone 5b
- 57702 zone 5a
- 57703 zone 5a
- 57709 zone 5b
Nearby cities
Questions
What growing zone is Rapid City, SD?
Rapid City is in USDA Plant Hardiness Zone 5b (average extreme winter low -15°F to -10°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 5a.
When is the last frost in Rapid City?
The average last spring frost (32°F) in Rapid City is May 3. There is still a 10% chance of frost until May 17.
When can I plant tomatoes in Rapid City?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 10 – May 17. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Rapid City Wfo, SD (USC00396948), 1.8 km (1.1 mi) from the city center, elevation 1030 m, based on 23 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.