Frost dates for 57621Bullhead, SD
The average last spring frost in Bullhead is May 12 and the average first fall frost is September 28, giving a typical growing season of about 137 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Sep 28
- Growing season
- 137 days
Safer after May 25 (1-in-10 risk)
Possible by Sep 16 (1-in-10 risk)
Last frost typically in 197 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 3 | Sep 9 · Sep 20 · Oct 1 | 120 days | 100% |
| Frost / freeze (32°F) | May 2 · May 12 · May 25 | Sep 16 · Sep 28 · Oct 9 | 137 days | 100% |
| Hard freeze (28°F) | Apr 19 · May 3 · May 16 | Sep 21 · Oct 5 · Oct 18 | 153 days | 100% |
Planting calendar for Bullhead
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 11 – Jun 17 |
| Tomatoes | Transplant outdoors | May 28 – Jun 8 |
| Peppers | Start seeds indoors | Apr 11 – May 12 |
| Peppers | Transplant outdoors | Jun 11 – Jul 12 |
| Eggplant | Start seeds indoors | Apr 28 – May 27 |
| Eggplant | Transplant outdoors | Jun 11 – Jul 12 |
| Cucumbers | Sow outdoors | Jun 11 – Jun 18 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 11 |
| Sweet corn | Sow outdoors | May 28 – Jun 8 |
| Watermelon & cantaloupe | Sow outdoors | Jun 11 – Jul 12 |
| Okra | Sow outdoors | Jun 4 – Jun 27 |
| Peas | Sow outdoors (spring) | Apr 11 – May 27 |
| Potatoes | Plant outdoors (spring) | Apr 11 – Jun 11 |
| Onions | Start seeds indoors (spring) | Feb 28 – Mar 27 |
| Onions | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (spring) | Mar 24 – Apr 27 |
| Broccoli | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (fall) | May 29 – Jun 8 |
| Broccoli | Transplant outdoors (fall) | Jun 28 – Jul 9 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 19 – Jun 18 |
| Cabbage | Transplant outdoors (fall) | Jun 18 – Jul 19 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 18 – Aug 4 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 5 – Aug 9 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 18 – Aug 19 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 11 – Jul 19 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 19 – Jul 4 |
| Garlic | Plant outdoors (fall) | Sep 18 – Oct 19 |
Where these dates come from
ZIP code 57621 is matched to the NOAA station Mc Laughlin, SD, 21.9 km away, at 2,001 ft elevation (226 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Mc Laughlin, SD (used) | 2,001 ft | May 12 | Sep 28 |
| Mc Intosh 6 Se, SD | 2,179 ft | May 9 | Sep 30 |
| Timber Lake, SD | 2,173 ft | May 10 | Sep 30 |
| Mobridge 2Nnw, SD | 1,693 ft | May 3 | Oct 8 |
Frost dates near Bullhead
- Mc Intosh, SD 57641 · last May 9, first Sep 30
- Walker, SD 57659 · last May 9, first Sep 30
- Mc Laughlin, SD 57642 · last May 12, first Sep 28
- Little Eagle, SD 57639 · last May 12, first Sep 28
- Selfridge, ND 58568 · last May 9, first Sep 30
- Glencross, SD 57630 · last May 10, first Sep 30
- Watauga, SD 57660 · last May 9, first Sep 30
- Timber Lake, SD 57656 · last May 10, first Sep 30
Frequently asked questions
- When is the last frost in Bullhead, SD?
- For ZIP code 57621, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Mc Laughlin, SD weather station. There is a 1-in-10 chance of a frost after May 25.
- When is the first frost in Bullhead, SD?
- The average first fall frost (32°F) is September 28. 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 57621?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 137 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.