Frost dates for 57430Britton, SD
The average last spring frost in Britton is May 13 and the average first fall frost is September 26, giving a typical growing season of about 135 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 13
- Average first fall frost
- Sep 26
- Growing season
- 135 days
Safer after May 27 (1-in-10 risk)
Possible by Sep 14 (1-in-10 risk)
Last frost typically in 198 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 9 · May 23 · Jun 5 | Sep 3 · Sep 16 · Sep 28 | 116 days | 100% |
| Frost / freeze (32°F) | Apr 29 · May 13 · May 27 | Sep 14 · Sep 26 · Oct 7 | 135 days | 100% |
| Hard freeze (28°F) | Apr 18 · May 2 · May 18 | Sep 23 · Oct 3 · Oct 18 | 153 days | 100% |
Planting calendar for Britton
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 12 – Jun 18 |
| Tomatoes | Transplant outdoors | May 29 – Jun 6 |
| Peppers | Start seeds indoors | Apr 12 – May 13 |
| Peppers | Transplant outdoors | Jun 12 – Jul 13 |
| Eggplant | Start seeds indoors | Apr 29 – May 28 |
| Eggplant | Transplant outdoors | Jun 12 – Jul 13 |
| Cucumbers | Sow outdoors | Jun 12 – Jun 16 |
| Summer squash | Sow outdoors | May 29 – Jul 13 |
| Winter squash & pumpkins | Sow outdoors | Jun 12 – Jul 13 |
| Snap beans | Sow outdoors | May 29 – Jul 9 |
| Sweet corn | Sow outdoors | May 29 – Jun 6 |
| Watermelon & cantaloupe | Sow outdoors | Jun 12 – Jul 13 |
| Okra | Sow outdoors | Jun 5 – Jun 28 |
| Peas | Sow outdoors (spring) | Apr 12 – May 28 |
| Potatoes | Plant outdoors (spring) | Apr 12 – Jun 12 |
| Onions | Start seeds indoors (spring) | Mar 1 – Mar 28 |
| Onions | Transplant outdoors (spring) | Apr 29 – May 28 |
| Broccoli | Start seeds indoors (spring) | Mar 25 – Apr 28 |
| Broccoli | Transplant outdoors (spring) | Apr 29 – May 28 |
| Broccoli | Start seeds indoors (fall) | May 27 – Jun 6 |
| Broccoli | Transplant outdoors (fall) | Jun 26 – Jul 7 |
| Cabbage | Start seeds indoors (spring) | Mar 15 – Apr 12 |
| Cabbage | Transplant outdoors (spring) | Apr 12 – May 13 |
| Cabbage | Start seeds indoors (fall) | May 17 – Jun 16 |
| Cabbage | Transplant outdoors (fall) | Jun 16 – Jul 17 |
| Leaf lettuce | Sow outdoors (spring) | Apr 12 – Jun 28 |
| Leaf lettuce | Sow outdoors (fall) | Jun 16 – Aug 2 |
| Spinach | Sow outdoors (spring) | Apr 5 – May 19 |
| Spinach | Sow outdoors (fall) | Jul 3 – Aug 7 |
| Radishes | Sow outdoors (spring) | Apr 12 – Jun 2 |
| Radishes | Sow outdoors (fall) | Jun 16 – Aug 17 |
| Kale | Sow outdoors (spring) | Apr 29 – May 19 |
| Kale | Sow outdoors (fall) | Jun 9 – Jul 17 |
| Carrots | Sow outdoors (spring) | May 13 – Jun 28 |
| Carrots | Sow outdoors (fall) | May 17 – Jul 2 |
| Garlic | Plant outdoors (fall) | Sep 16 – Oct 17 |
Where these dates come from
ZIP code 57430 is matched to the NOAA station Britton, SD, 1.6 km away, at 1,355 ft elevation (43 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Britton, SD (used) | 1,355 ft | May 13 | Sep 26 |
| Roy Lake, SD | 1,810 ft | May 2 | Oct 9 |
| Forman 5 Sse, ND | 1,250 ft | May 7 | Oct 1 |
| Columbia 8 N, SD | 1,305 ft | May 7 | Sep 29 |
Frost dates near Britton
- Amherst, SD 57421 · last May 13, first Sep 26
- Havana, ND 58043 · last May 7, first Oct 1
- Langford, SD 57454 · last May 13, first Sep 26
- Houghton, SD 57449 · last May 7, first Sep 29
- Claremont, SD 57432 · last May 7, first Sep 29
- Cogswell, ND 58017 · last May 7, first Oct 1
- Forman, ND 58032 · last May 7, first Oct 1
- Lake City, SD 57247 · last May 2, first Oct 9
Frequently asked questions
- When is the last frost in Britton, SD?
- For ZIP code 57430, the average last spring frost (32°F) is May 13, based on NOAA 1991-2020 climate normals for the Britton, SD weather station. There is a 1-in-10 chance of a frost after May 27.
- When is the first frost in Britton, SD?
- The average first fall frost (32°F) is September 26. There is a 1-in-10 chance of frost by September 14, so tender plants are at risk from that point on.
- How long is the growing season in 57430?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 135 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.