Frost dates for 59772Bozeman, MT
The average last spring frost in Bozeman is May 26 and the average first fall frost is September 22, giving a typical growing season of about 116 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 26
- Average first fall frost
- Sep 22
- Growing season
- 116 days
Safer after Jun 14 (1-in-10 risk)
Possible by Sep 5 (1-in-10 risk)
Last frost typically in 211 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 28 · Jun 14 · Jun 28 | Aug 26 · Sep 8 · Sep 23 | 87 days | 100% |
| Frost / freeze (32°F) | May 9 · May 26 · Jun 14 | Sep 5 · Sep 22 · Oct 5 | 116 days | 100% |
| Hard freeze (28°F) | Apr 23 · May 8 · May 26 | Sep 18 · Oct 3 · Oct 19 | 147 days | 100% |
Planting calendar for Bozeman
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 25 – Jul 1 |
| Tomatoes | Transplant outdoors | Jun 11 – Jun 2 |
| Peppers | Start seeds indoors | Apr 25 – May 26 |
| Peppers | Transplant outdoors | Jun 25 – Jul 26 |
| Eggplant | Start seeds indoors | May 12 – Jun 10 |
| Eggplant | Transplant outdoors | Jun 25 – Jul 26 |
| Cucumbers | Sow outdoors | Jun 25 – Jun 12 |
| Summer squash | Sow outdoors | Jun 11 – Jul 26 |
| Winter squash & pumpkins | Sow outdoors | Jun 25 – Jul 26 |
| Snap beans | Sow outdoors | Jun 11 – Jul 5 |
| Sweet corn | Sow outdoors | Jun 11 – Jun 2 |
| Watermelon & cantaloupe | Sow outdoors | Jun 25 – Jul 26 |
| Okra | Sow outdoors | Jun 18 – Jul 11 |
| Peas | Sow outdoors (spring) | Apr 25 – Jun 10 |
| Potatoes | Plant outdoors (spring) | Apr 25 – Jun 25 |
| Onions | Start seeds indoors (spring) | Mar 14 – Apr 10 |
| Onions | Transplant outdoors (spring) | May 12 – Jun 10 |
| Broccoli | Start seeds indoors (spring) | Apr 7 – May 11 |
| Broccoli | Transplant outdoors (spring) | May 12 – Jun 10 |
| Broccoli | Start seeds indoors (fall) | May 23 – Jun 2 |
| Broccoli | Transplant outdoors (fall) | Jun 22 – Jul 3 |
| Cabbage | Start seeds indoors (spring) | Mar 28 – Apr 25 |
| Cabbage | Transplant outdoors (spring) | Apr 25 – May 26 |
| Cabbage | Start seeds indoors (fall) | May 13 – Jun 12 |
| Cabbage | Transplant outdoors (fall) | Jun 12 – Jul 13 |
| Leaf lettuce | Sow outdoors (spring) | Apr 25 – Jul 11 |
| Leaf lettuce | Sow outdoors (fall) | Jun 12 – Jul 29 |
| Spinach | Sow outdoors (spring) | Apr 18 – Jun 1 |
| Spinach | Sow outdoors (fall) | Jun 29 – Aug 3 |
| Radishes | Sow outdoors (spring) | Apr 25 – Jun 15 |
| Radishes | Sow outdoors (fall) | Jun 12 – Aug 13 |
| Kale | Sow outdoors (spring) | May 12 – Jun 1 |
| Kale | Sow outdoors (fall) | Jun 5 – Jul 13 |
| Carrots | Sow outdoors (spring) | May 26 – Jul 11 |
| Carrots | Sow outdoors (fall) | May 13 – Jun 28 |
| Garlic | Plant outdoors (fall) | Sep 12 – Oct 13 |
Where these dates come from
ZIP code 59772 is matched to the NOAA station Bozeman Montana State Univ, MT, 3.2 km away, at 4,913 ft elevation (143 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Bozeman Montana State Univ, MT (used) | 4,913 ft | May 26 | Sep 22 |
| Bozeman 6 W Exp Farm, MT | 4,775 ft | May 23 | Sep 23 |
| Bozeman Gallatin Fld, MT | 4,427 ft | May 26 | Sep 16 |
| Logan Landfill, MT | 4,243 ft | May 26 | Sep 15 |
Frost dates near Bozeman
- Bozeman, MT 59715 · last May 26, first Sep 22
- Belgrade, MT 59714 · last May 26, first Sep 16
- Manhattan, MT 59741 · last May 26, first Sep 16
- Gallatin Gateway, MT 59730 · last —, first —
- Livingston, MT 59047 · last May 27, first Sep 14
- Clyde Park, MT 59018 · last May 27, first Sep 14
- Pray, MT 59065 · last May 19, first Sep 25
- Big Sky, MT 59716 · last —, first —
Frequently asked questions
- When is the last frost in Bozeman, MT?
- For ZIP code 59772, the average last spring frost (32°F) is May 26, based on NOAA 1991-2020 climate normals for the Bozeman Montana State Univ, MT weather station. There is a 1-in-10 chance of a frost after June 14.
- When is the first frost in Bozeman, MT?
- The average first fall frost (32°F) is September 22. There is a 1-in-10 chance of frost by September 5, so tender plants are at risk from that point on.
- How long is the growing season in 59772?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 116 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.