Frost dates for 58640Killdeer, ND
The average last spring frost in Killdeer is May 21 and the average first fall frost is September 23, giving a typical growing season of about 124 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 21
- Average first fall frost
- Sep 23
- Growing season
- 124 days
Safer after Jun 5 (1-in-10 risk)
Possible by Sep 8 (1-in-10 risk)
Last frost typically in 207 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 20 · Jun 1 · Jun 16 | Aug 29 · Sep 13 · Sep 25 | 103 days | 100% |
| Frost / freeze (32°F) | May 9 · May 21 · Jun 5 | Sep 8 · Sep 23 · Oct 5 | 124 days | 100% |
| Hard freeze (28°F) | Apr 29 · May 10 · May 24 | Sep 19 · Oct 1 · Oct 14 | 143 days | 100% |
Planting calendar for Killdeer
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 20 – Jun 26 |
| Tomatoes | Transplant outdoors | Jun 6 – Jun 3 |
| Peppers | Start seeds indoors | Apr 20 – May 21 |
| Peppers | Transplant outdoors | Jun 20 – Jul 21 |
| Eggplant | Start seeds indoors | May 7 – Jun 5 |
| Eggplant | Transplant outdoors | Jun 20 – Jul 21 |
| Cucumbers | Sow outdoors | Jun 20 – Jun 13 |
| Summer squash | Sow outdoors | Jun 6 – Jul 21 |
| Winter squash & pumpkins | Sow outdoors | Jun 20 – Jul 21 |
| Snap beans | Sow outdoors | Jun 6 – Jul 6 |
| Sweet corn | Sow outdoors | Jun 6 – Jun 3 |
| Watermelon & cantaloupe | Sow outdoors | Jun 20 – Jul 21 |
| Okra | Sow outdoors | Jun 13 – Jul 6 |
| Peas | Sow outdoors (spring) | Apr 20 – Jun 5 |
| Potatoes | Plant outdoors (spring) | Apr 20 – Jun 20 |
| Onions | Start seeds indoors (spring) | Mar 9 – Apr 5 |
| Onions | Transplant outdoors (spring) | May 7 – Jun 5 |
| Broccoli | Start seeds indoors (spring) | Apr 2 – May 6 |
| Broccoli | Transplant outdoors (spring) | May 7 – Jun 5 |
| Broccoli | Start seeds indoors (fall) | May 24 – Jun 3 |
| Broccoli | Transplant outdoors (fall) | Jun 23 – Jul 4 |
| Cabbage | Start seeds indoors (spring) | Mar 23 – Apr 20 |
| Cabbage | Transplant outdoors (spring) | Apr 20 – May 21 |
| Cabbage | Start seeds indoors (fall) | May 14 – Jun 13 |
| Cabbage | Transplant outdoors (fall) | Jun 13 – Jul 14 |
| Leaf lettuce | Sow outdoors (spring) | Apr 20 – Jul 6 |
| Leaf lettuce | Sow outdoors (fall) | Jun 13 – Jul 30 |
| Spinach | Sow outdoors (spring) | Apr 13 – May 27 |
| Spinach | Sow outdoors (fall) | Jun 30 – Aug 4 |
| Radishes | Sow outdoors (spring) | Apr 20 – Jun 10 |
| Radishes | Sow outdoors (fall) | Jun 13 – Aug 14 |
| Kale | Sow outdoors (spring) | May 7 – May 27 |
| Kale | Sow outdoors (fall) | Jun 6 – Jul 14 |
| Carrots | Sow outdoors (spring) | May 21 – Jul 6 |
| Carrots | Sow outdoors (fall) | May 14 – Jun 29 |
| Garlic | Plant outdoors (fall) | Sep 13 – Oct 14 |
Where these dates come from
ZIP code 58640 is matched to the NOAA station Killdeer, ND, 4.5 km away, at 2,310 ft elevation (10 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Killdeer, ND (used) | 2,310 ft | May 21 | Sep 23 |
| Dunn Ctr 1E, ND | 2,187 ft | May 20 | Sep 21 |
| Dickinson Rch Hq, ND | 2,380 ft | May 18 | Sep 24 |
| Grassy Butte 2Ene, ND | 2,670 ft | May 18 | Sep 23 |
Frost dates near Killdeer
- Dunn Center, ND 58626 · last May 20, first Sep 21
- Manning, ND 58642 · last May 18, first Sep 24
- Halliday, ND 58636 · last May 20, first Sep 21
- Mandaree, ND 58757 · last May 20, first Sep 20
- Grassy Butte, ND 58634 · last May 18, first Sep 23
- Fairfield, ND 58627 · last May 12, first Sep 28
- Dodge, ND 58625 · last May 20, first Sep 21
- Marshall, ND 58644 · last May 23, first Sep 20
Frequently asked questions
- When is the last frost in Killdeer, ND?
- For ZIP code 58640, the average last spring frost (32°F) is May 21, based on NOAA 1991-2020 climate normals for the Killdeer, ND weather station. There is a 1-in-10 chance of a frost after June 5.
- When is the first frost in Killdeer, ND?
- The average first fall frost (32°F) is September 23. There is a 1-in-10 chance of frost by September 8, so tender plants are at risk from that point on.
- How long is the growing season in 58640?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 124 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.