Frost dates for 57266Summit, SD
The average last spring frost in Summit is May 14 and the average first fall frost is September 28, giving a typical growing season of about 136 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 14
- Average first fall frost
- Sep 28
- Growing season
- 136 days
Safer after May 28 (1-in-10 risk)
Possible by Sep 13 (1-in-10 risk)
Last frost typically in 199 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 12 · May 24 · Jun 7 | Sep 4 · Sep 18 · Oct 1 | 117 days | 100% |
| Frost / freeze (32°F) | May 1 · May 14 · May 28 | Sep 13 · Sep 28 · Oct 10 | 136 days | 100% |
| Hard freeze (28°F) | Apr 21 · May 4 · May 17 | Sep 24 · Oct 4 · Oct 19 | 153 days | 100% |
Planting calendar for Summit
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 13 – Jun 19 |
| Tomatoes | Transplant outdoors | May 30 – Jun 8 |
| Peppers | Start seeds indoors | Apr 13 – May 14 |
| Peppers | Transplant outdoors | Jun 13 – Jul 14 |
| Eggplant | Start seeds indoors | Apr 30 – May 29 |
| Eggplant | Transplant outdoors | Jun 13 – Jul 14 |
| Cucumbers | Sow outdoors | Jun 13 – Jun 18 |
| Summer squash | Sow outdoors | May 30 – Jul 14 |
| Winter squash & pumpkins | Sow outdoors | Jun 13 – Jul 14 |
| Snap beans | Sow outdoors | May 30 – Jul 11 |
| Sweet corn | Sow outdoors | May 30 – Jun 8 |
| Watermelon & cantaloupe | Sow outdoors | Jun 13 – Jul 14 |
| Okra | Sow outdoors | Jun 6 – Jun 29 |
| Peas | Sow outdoors (spring) | Apr 13 – May 29 |
| Potatoes | Plant outdoors (spring) | Apr 13 – Jun 13 |
| Onions | Start seeds indoors (spring) | Mar 2 – Mar 29 |
| Onions | Transplant outdoors (spring) | Apr 30 – May 29 |
| Broccoli | Start seeds indoors (spring) | Mar 26 – Apr 29 |
| Broccoli | Transplant outdoors (spring) | Apr 30 – May 29 |
| Broccoli | Start seeds indoors (fall) | May 29 – Jun 8 |
| Broccoli | Transplant outdoors (fall) | Jun 28 – Jul 9 |
| Cabbage | Start seeds indoors (spring) | Mar 16 – Apr 13 |
| Cabbage | Transplant outdoors (spring) | Apr 13 – May 14 |
| Cabbage | Start seeds indoors (fall) | May 19 – Jun 18 |
| Cabbage | Transplant outdoors (fall) | Jun 18 – Jul 19 |
| Leaf lettuce | Sow outdoors (spring) | Apr 13 – Jun 29 |
| Leaf lettuce | Sow outdoors (fall) | Jun 18 – Aug 4 |
| Spinach | Sow outdoors (spring) | Apr 6 – May 20 |
| Spinach | Sow outdoors (fall) | Jul 5 – Aug 9 |
| Radishes | Sow outdoors (spring) | Apr 13 – Jun 3 |
| Radishes | Sow outdoors (fall) | Jun 18 – Aug 19 |
| Kale | Sow outdoors (spring) | Apr 30 – May 20 |
| Kale | Sow outdoors (fall) | Jun 11 – Jul 19 |
| Carrots | Sow outdoors (spring) | May 14 – Jun 29 |
| Carrots | Sow outdoors (fall) | May 19 – Jul 4 |
| Garlic | Plant outdoors (fall) | Sep 18 – Oct 19 |
Where these dates come from
ZIP code 57266 is matched to the NOAA station Summit 1 W, SD, 5.6 km away, at 1,955 ft elevation (36 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Summit 1 W, SD (used) | 1,955 ft | May 14 | Sep 28 |
| Wilmot, SD | 1,201 ft | May 5 | Oct 1 |
| Waubay Natl Wild Life, SD | 1,827 ft | May 1 | Oct 12 |
| Milbank 4 Nw, SD | 1,145 ft | May 2 | Oct 4 |
Frost dates near Summit
- Marvin, SD 57251 · last May 14, first Sep 28
- Ortley, SD 57256 · last May 14, first Sep 28
- Wilmot, SD 57279 · last May 5, first Oct 1
- Peever, SD 57257 · last May 4, first Oct 3
- Waubay, SD 57273 · last May 1, first Oct 12
- Twin Brooks, SD 57269 · last May 5, first Oct 1
- Grenville, SD 57239 · last May 1, first Oct 12
- South Shore, SD 57263 · last May 14, first Sep 28
Frequently asked questions
- When is the last frost in Summit, SD?
- For ZIP code 57266, the average last spring frost (32°F) is May 14, based on NOAA 1991-2020 climate normals for the Summit 1 W, SD weather station. There is a 1-in-10 chance of a frost after May 28.
- When is the first frost in Summit, SD?
- The average first fall frost (32°F) is September 28. There is a 1-in-10 chance of frost by September 13, so tender plants are at risk from that point on.
- How long is the growing season in 57266?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 136 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.