Frost dates for 59006Ballantine, MT
The average last spring frost in Ballantine is May 12 and the average first fall frost is September 25, giving a typical growing season of about 136 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Sep 25
- Growing season
- 136 days
Safer after May 26 (1-in-10 risk)
Possible by Sep 13 (1-in-10 risk)
Last frost typically in 197 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 13 · May 25 · Jun 10 | Sep 1 · Sep 14 · Sep 29 | 111 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 12 · May 26 | Sep 13 · Sep 25 · Oct 8 | 136 days | 100% |
| Hard freeze (28°F) | Apr 15 · Apr 30 · May 14 | Sep 23 · Oct 4 · Oct 18 | 157 days | 100% |
Planting calendar for Ballantine
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 11 – Jun 17 |
| Tomatoes | Transplant outdoors | May 28 – Jun 5 |
| Peppers | Start seeds indoors | Apr 11 – May 12 |
| Peppers | Transplant outdoors | Jun 11 – Jul 12 |
| Eggplant | Start seeds indoors | Apr 28 – May 27 |
| Eggplant | Transplant outdoors | Jun 11 – Jul 12 |
| Cucumbers | Sow outdoors | Jun 11 – Jun 15 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 8 |
| Sweet corn | Sow outdoors | May 28 – Jun 5 |
| Watermelon & cantaloupe | Sow outdoors | Jun 11 – Jul 12 |
| Okra | Sow outdoors | Jun 4 – Jun 27 |
| Peas | Sow outdoors (spring) | Apr 11 – May 27 |
| Potatoes | Plant outdoors (spring) | Apr 11 – Jun 11 |
| Onions | Start seeds indoors (spring) | Feb 28 – Mar 27 |
| Onions | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (spring) | Mar 24 – Apr 27 |
| Broccoli | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (fall) | May 26 – Jun 5 |
| Broccoli | Transplant outdoors (fall) | Jun 25 – Jul 6 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 16 – Jun 15 |
| Cabbage | Transplant outdoors (fall) | Jun 15 – Jul 16 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 15 – Aug 1 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 2 – Aug 6 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 15 – Aug 16 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 8 – Jul 16 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 16 – Jul 1 |
| Garlic | Plant outdoors (fall) | Sep 15 – Oct 16 |
Where these dates come from
ZIP code 59006 is matched to the NOAA station Huntley Exp Stn, MT, 10.1 km away, at 3,034 ft elevation (49 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Huntley Exp Stn, MT (used) | 3,034 ft | May 12 | Sep 25 |
| Pompeys Pillar 15N, MT | 3,390 ft | May 22 | Sep 22 |
| Billings Wtp, MT | 3,097 ft | May 10 | Oct 1 |
| Billings Logan Intl Ap, MT | 3,581 ft | May 4 | Oct 7 |
Frost dates near Ballantine
- Worden, MT 59088 · last May 12, first Sep 25
- Huntley, MT 59037 · last May 12, first Sep 25
- Pompeys Pillar, MT 59064 · last May 12, first Sep 25
- Shepherd, MT 59079 · last May 12, first Sep 25
- Billings, MT 59107 · last May 10, first Oct 1
- Acton, MT 59002 · last May 4, first Oct 7
- Custer, MT 59024 · last May 10, first Sep 29
- Hardin, MT 59034 · last May 13, first Sep 29
Frequently asked questions
- When is the last frost in Ballantine, MT?
- For ZIP code 59006, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Huntley Exp Stn, MT weather station. There is a 1-in-10 chance of a frost after May 26.
- When is the first frost in Ballantine, MT?
- The average first fall frost (32°F) is September 25. 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 59006?
- 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.