When to plant in Spearfish, SD
USDA Zone 5bSpearfish, South Dakota frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
In zone 5b, Spearfish gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
The average last spring frost in Spearfish is now 12 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
SPEARFISH · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Spearfish’s own odds, recorded at SPEARFISH.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 4 | May 22 | May 11 | Sep 9 | Sep 25 | Oct 6 |
| 32°F | May 25 | May 12 | Apr 29 | Sep 21 | Oct 2 | Oct 17 |
| 28°F | May 14 | Apr 30 | Apr 16 | Sep 29 | Oct 12 | Oct 25 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Spearfish, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 16 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Spearfish planting FAQ
When is the last spring frost in Spearfish, SD?
Plan for the last spring frost in Spearfish around May 12 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Spearfish, SD?
The first fall frost in Spearfish typically arrives around October 2 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Spearfish in?
Spearfish is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Spearfish?
Spearfish has about 143 frost-free days — a short growing season — between the average last spring frost (May 12) and first fall frost (October 2).
When should I plant tomatoes in Spearfish?
For Spearfish, sow tomatoes indoors about March 17–March 31 and move the seedlings out around May 19, after the last spring frost.
Never miss a window in Spearfish
An email when it’s time to start seeds, transplant, and sow — timed to Spearfish’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Rapid City · 67 km
- Box Elder · 72 km
- Gillette · 136 km
- Sheridan · 251 km
- Casper · 272 km
- Pierre · 278 km
- Dickinson · 279 km
- Scottsbluff · 292 km
Frost dates recorded at SPEARFISH, 4 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Spearfish, SD — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00397882. Retrieved from https://blissgarden.com/south-dakota/spearfish.