Frost dates for 58655South Heart, ND
The average last spring frost in South Heart is May 18 and the average first fall frost is September 25, giving a typical growing season of about 129 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 18
- Average first fall frost
- Sep 25
- Growing season
- 129 days
Safer after May 31 (1-in-10 risk)
Possible by Sep 12 (1-in-10 risk)
Last frost typically in 203 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 16 · May 29 · Jun 12 | Sep 3 · Sep 16 · Sep 28 | 109 days | 100% |
| Frost / freeze (32°F) | May 6 · May 18 · May 31 | Sep 12 · Sep 25 · Oct 7 | 129 days | 100% |
| Hard freeze (28°F) | Apr 26 · May 8 · May 22 | Sep 22 · Oct 3 · Oct 16 | 147 days | 100% |
Planting calendar for South Heart
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 17 – Jun 23 |
| Tomatoes | Transplant outdoors | Jun 3 – Jun 5 |
| Peppers | Start seeds indoors | Apr 17 – May 18 |
| Peppers | Transplant outdoors | Jun 17 – Jul 18 |
| Eggplant | Start seeds indoors | May 4 – Jun 2 |
| Eggplant | Transplant outdoors | Jun 17 – Jul 18 |
| Cucumbers | Sow outdoors | Jun 17 – Jun 15 |
| Summer squash | Sow outdoors | Jun 3 – Jul 18 |
| Winter squash & pumpkins | Sow outdoors | Jun 17 – Jul 18 |
| Snap beans | Sow outdoors | Jun 3 – Jul 8 |
| Sweet corn | Sow outdoors | Jun 3 – Jun 5 |
| Watermelon & cantaloupe | Sow outdoors | Jun 17 – Jul 18 |
| Okra | Sow outdoors | Jun 10 – Jul 3 |
| Peas | Sow outdoors (spring) | Apr 17 – Jun 2 |
| Potatoes | Plant outdoors (spring) | Apr 17 – Jun 17 |
| Onions | Start seeds indoors (spring) | Mar 6 – Apr 2 |
| Onions | Transplant outdoors (spring) | May 4 – Jun 2 |
| Broccoli | Start seeds indoors (spring) | Mar 30 – May 3 |
| Broccoli | Transplant outdoors (spring) | May 4 – Jun 2 |
| Broccoli | Start seeds indoors (fall) | May 26 – Jun 5 |
| Broccoli | Transplant outdoors (fall) | Jun 25 – Jul 6 |
| Cabbage | Start seeds indoors (spring) | Mar 20 – Apr 17 |
| Cabbage | Transplant outdoors (spring) | Apr 17 – May 18 |
| Cabbage | Start seeds indoors (fall) | May 16 – Jun 15 |
| Cabbage | Transplant outdoors (fall) | Jun 15 – Jul 16 |
| Leaf lettuce | Sow outdoors (spring) | Apr 17 – Jul 3 |
| Leaf lettuce | Sow outdoors (fall) | Jun 15 – Aug 1 |
| Spinach | Sow outdoors (spring) | Apr 10 – May 24 |
| Spinach | Sow outdoors (fall) | Jul 2 – Aug 6 |
| Radishes | Sow outdoors (spring) | Apr 17 – Jun 7 |
| Radishes | Sow outdoors (fall) | Jun 15 – Aug 16 |
| Kale | Sow outdoors (spring) | May 4 – May 24 |
| Kale | Sow outdoors (fall) | Jun 8 – Jul 16 |
| Carrots | Sow outdoors (spring) | May 18 – Jul 3 |
| Carrots | Sow outdoors (fall) | May 16 – Jul 1 |
| Garlic | Plant outdoors (fall) | Sep 15 – Oct 16 |
Where these dates come from
ZIP code 58655 is matched to the NOAA station Theodore Roosevelt Ap, ND, 16.7 km away, at 2,580 ft elevation (15 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Theodore Roosevelt Ap, ND (used) | 2,580 ft | May 18 | Sep 25 |
| Dickinson, ND | 2,460 ft | May 20 | Sep 22 |
| Medora 7 E, ND | 2,771 ft | May 9 | Sep 30 |
| New England, ND | 2,600 ft | May 16 | Sep 24 |
Frost dates near South Heart
- Belfield, ND 58622 · last May 9, first Sep 30
- Dickinson, ND 58602 · last May 20, first Sep 22
- New England, ND 58647 · last May 16, first Sep 24
- Gladstone, ND 58630 · last May 23, first Sep 20
- Lefor, ND 58641 · last May 18, first Sep 25
- Manning, ND 58642 · last May 18, first Sep 24
- Medora, ND 58645 · last May 19, first Sep 20
- Amidon, ND 58620 · last May 12, first Sep 29
Frequently asked questions
- When is the last frost in South Heart, ND?
- For ZIP code 58655, the average last spring frost (32°F) is May 18, based on NOAA 1991-2020 climate normals for the Theodore Roosevelt Ap, ND weather station. There is a 1-in-10 chance of a frost after May 31.
- When is the first frost in South Heart, ND?
- The average first fall frost (32°F) is September 25. There is a 1-in-10 chance of frost by September 12, so tender plants are at risk from that point on.
- How long is the growing season in 58655?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 129 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.