Frost dates for 59212Bainville, MT
The average last spring frost in Bainville is May 21 and the average first fall frost is September 20, giving a typical growing season of about 120 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 21
- Average first fall frost
- Sep 20
- Growing season
- 120 days
Safer after Jun 3 (1-in-10 risk)
Possible by Sep 6 (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 19 · May 31 · Jun 16 | Aug 30 · Sep 10 · Sep 21 | 101 days | 100% |
| Frost / freeze (32°F) | May 8 · May 21 · Jun 3 | Sep 6 · Sep 20 · Sep 30 | 120 days | 100% |
| Hard freeze (28°F) | Apr 29 · May 10 · May 24 | Sep 13 · Sep 27 · Oct 11 | 138 days | 100% |
Planting calendar for Bainville
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 – May 31 |
| 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 10 |
| Summer squash | Sow outdoors | Jun 6 – Jul 21 |
| Winter squash & pumpkins | Sow outdoors | Jun 20 – Jul 21 |
| Snap beans | Sow outdoors | Jun 6 – Jul 3 |
| Sweet corn | Sow outdoors | Jun 6 – May 31 |
| 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 21 – May 31 |
| Broccoli | Transplant outdoors (fall) | Jun 20 – Jul 1 |
| Cabbage | Start seeds indoors (spring) | Mar 23 – Apr 20 |
| Cabbage | Transplant outdoors (spring) | Apr 20 – May 21 |
| Cabbage | Start seeds indoors (fall) | May 11 – Jun 10 |
| Cabbage | Transplant outdoors (fall) | Jun 10 – Jul 11 |
| Leaf lettuce | Sow outdoors (spring) | Apr 20 – Jul 6 |
| Leaf lettuce | Sow outdoors (fall) | Jun 10 – Jul 27 |
| Spinach | Sow outdoors (spring) | Apr 13 – May 27 |
| Spinach | Sow outdoors (fall) | Jun 27 – Aug 1 |
| Radishes | Sow outdoors (spring) | Apr 20 – Jun 10 |
| Radishes | Sow outdoors (fall) | Jun 10 – Aug 11 |
| Kale | Sow outdoors (spring) | May 7 – May 27 |
| Kale | Sow outdoors (fall) | Jun 3 – Jul 11 |
| Carrots | Sow outdoors (spring) | May 21 – Jul 6 |
| Carrots | Sow outdoors (fall) | May 11 – Jun 26 |
| Garlic | Plant outdoors (fall) | Sep 10 – Oct 11 |
Where these dates come from
ZIP code 59212 is matched to the NOAA station Culbertson, MT, 23 km away, at 1,940 ft elevation (183 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Culbertson, MT (used) | 1,940 ft | May 21 | Sep 20 |
| Williston Exp Farm, ND | 2,105 ft | May 13 | Sep 26 |
| Medicine Lake 3 Se, MT | 1,942 ft | May 16 | Sep 18 |
| Williston Sloulin Intl Ap, ND | 1,902 ft | May 21 | Sep 21 |
Frost dates near Bainville
- Culbertson, MT 59218 · last May 21, first Sep 20
- Trenton, ND 58853 · last May 21, first Sep 21
- Froid, MT 59226 · last May 16, first Sep 18
- Fairview, MT 59221 · last May 11, first Sep 27
- Homestead, MT 59242 · last May 16, first Sep 18
- Medicine Lake, MT 59247 · last May 16, first Sep 18
- Williston, ND 58801 · last May 21, first Sep 21
- Cartwright, ND 58838 · last May 11, first Sep 27
Frequently asked questions
- When is the last frost in Bainville, MT?
- For ZIP code 59212, the average last spring frost (32°F) is May 21, based on NOAA 1991-2020 climate normals for the Culbertson, MT weather station. There is a 1-in-10 chance of a frost after June 3.
- When is the first frost in Bainville, MT?
- The average first fall frost (32°F) is September 20. There is a 1-in-10 chance of frost by September 6, so tender plants are at risk from that point on.
- How long is the growing season in 59212?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 120 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.