Frost dates for 59318Brusett, MT
The average last spring frost in Brusett is May 18 and the average first fall frost is September 20, giving a typical growing season of about 123 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 18
- Average first fall frost
- Sep 20
- Growing season
- 123 days
Safer after May 31 (1-in-10 risk)
Possible by Sep 8 (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 17 · May 29 · Jun 14 | Aug 28 · Sep 11 · Sep 22 | 103 days | 100% |
| Frost / freeze (32°F) | May 6 · May 18 · May 31 | Sep 8 · Sep 20 · Oct 1 | 123 days | 100% |
| Hard freeze (28°F) | Apr 24 · May 8 · May 21 | Sep 17 · Sep 29 · Oct 11 | 143 days | 100% |
Planting calendar for Brusett
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 – May 31 |
| 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 10 |
| Summer squash | Sow outdoors | Jun 3 – Jul 18 |
| Winter squash & pumpkins | Sow outdoors | Jun 17 – Jul 18 |
| Snap beans | Sow outdoors | Jun 3 – Jul 3 |
| Sweet corn | Sow outdoors | Jun 3 – May 31 |
| 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 21 – May 31 |
| Broccoli | Transplant outdoors (fall) | Jun 20 – Jul 1 |
| Cabbage | Start seeds indoors (spring) | Mar 20 – Apr 17 |
| Cabbage | Transplant outdoors (spring) | Apr 17 – May 18 |
| Cabbage | Start seeds indoors (fall) | May 11 – Jun 10 |
| Cabbage | Transplant outdoors (fall) | Jun 10 – Jul 11 |
| Leaf lettuce | Sow outdoors (spring) | Apr 17 – Jul 3 |
| Leaf lettuce | Sow outdoors (fall) | Jun 10 – Jul 27 |
| Spinach | Sow outdoors (spring) | Apr 10 – May 24 |
| Spinach | Sow outdoors (fall) | Jun 27 – Aug 1 |
| Radishes | Sow outdoors (spring) | Apr 17 – Jun 7 |
| Radishes | Sow outdoors (fall) | Jun 10 – Aug 11 |
| Kale | Sow outdoors (spring) | May 4 – May 24 |
| Kale | Sow outdoors (fall) | Jun 3 – Jul 11 |
| Carrots | Sow outdoors (spring) | May 18 – Jul 3 |
| Carrots | Sow outdoors (fall) | May 11 – Jun 26 |
| Garlic | Plant outdoors (fall) | Sep 10 – Oct 11 |
Where these dates come from
ZIP code 59318 is matched to the NOAA station Jordan Ap, MT, 26.5 km away, at 2,662 ft elevation (245 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Jordan Ap, MT (used) | 2,662 ft | May 18 | Sep 20 |
| Jordan, MT | 2,620 ft | May 21 | Sep 18 |
| Mosby 4 Ene, MT | 2,910 ft | May 5 | Oct 4 |
| Cohagen, MT | 2,720 ft | May 25 | Sep 14 |
Frost dates near Brusett
- Jordan, MT 59337 · last May 21, first Sep 18
- Sand Springs, MT 59077 · last May 5, first Oct 4
- Cohagen, MT 59322 · last May 25, first Sep 14
- Mosby, MT 59058 · last May 5, first Oct 4
- Fort Peck, MT 59223 · last May 8, first Oct 1
- Sumatra, MT 59083 · last May 10, first Sep 29
- Ingomar, MT 59039 · last May 21, first Sep 19
- Winnett, MT 59087 · last May 16, first Sep 28
Frequently asked questions
- When is the last frost in Brusett, MT?
- For ZIP code 59318, the average last spring frost (32°F) is May 18, based on NOAA 1991-2020 climate normals for the Jordan Ap, MT weather station. There is a 1-in-10 chance of a frost after May 31.
- When is the first frost in Brusett, MT?
- The average first fall frost (32°F) is September 20. 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 59318?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 123 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.