Frost dates for 59213Brockton, MT
The average last spring frost in Brockton is May 24 and the average first fall frost is September 14, giving a typical growing season of about 110 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 24
- Average first fall frost
- Sep 14
- Growing season
- 110 days
Safer after Jun 6 (1-in-10 risk)
Possible by Sep 1 (1-in-10 risk)
Last frost typically in 209 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 21 · Jun 3 · Jun 24 | Aug 21 · Sep 4 · Sep 16 | 90 days | 100% |
| Frost / freeze (32°F) | May 12 · May 24 · Jun 6 | Sep 1 · Sep 14 · Sep 25 | 110 days | 100% |
| Hard freeze (28°F) | May 1 · May 14 · May 26 | Sep 8 · Sep 22 · Oct 4 | 130 days | 100% |
Planting calendar for Brockton
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 23 – Jun 29 |
| Tomatoes | Transplant outdoors | Jun 9 – May 25 |
| Peppers | Start seeds indoors | Apr 23 – May 24 |
| Peppers | Transplant outdoors | Jun 23 – Jul 24 |
| Eggplant | Start seeds indoors | May 10 – Jun 8 |
| Eggplant | Transplant outdoors | Jun 23 – Jul 24 |
| Cucumbers | Sow outdoors | Jun 23 – Jun 4 |
| Summer squash | Sow outdoors | Jun 9 – Jul 24 |
| Winter squash & pumpkins | Sow outdoors | Jun 23 – Jul 24 |
| Snap beans | Sow outdoors | Jun 9 – Jun 27 |
| Sweet corn | Sow outdoors | Jun 9 – May 25 |
| Watermelon & cantaloupe | Sow outdoors | Jun 23 – Jul 24 |
| Okra | Sow outdoors | Jun 16 – Jul 9 |
| Peas | Sow outdoors (spring) | Apr 23 – Jun 8 |
| Potatoes | Plant outdoors (spring) | Apr 23 – Jun 23 |
| Onions | Start seeds indoors (spring) | Mar 12 – Apr 8 |
| Onions | Transplant outdoors (spring) | May 10 – Jun 8 |
| Broccoli | Start seeds indoors (spring) | Apr 5 – May 9 |
| Broccoli | Transplant outdoors (spring) | May 10 – Jun 8 |
| Broccoli | Start seeds indoors (fall) | May 15 – May 25 |
| Broccoli | Transplant outdoors (fall) | Jun 14 – Jun 25 |
| Cabbage | Start seeds indoors (spring) | Mar 26 – Apr 23 |
| Cabbage | Transplant outdoors (spring) | Apr 23 – May 24 |
| Cabbage | Start seeds indoors (fall) | May 5 – Jun 4 |
| Cabbage | Transplant outdoors (fall) | Jun 4 – Jul 5 |
| Leaf lettuce | Sow outdoors (spring) | Apr 23 – Jul 9 |
| Leaf lettuce | Sow outdoors (fall) | Jun 4 – Jul 21 |
| Spinach | Sow outdoors (spring) | Apr 16 – May 30 |
| Spinach | Sow outdoors (fall) | Jun 21 – Jul 26 |
| Radishes | Sow outdoors (spring) | Apr 23 – Jun 13 |
| Radishes | Sow outdoors (fall) | Jun 4 – Aug 5 |
| Kale | Sow outdoors (spring) | May 10 – May 30 |
| Kale | Sow outdoors (fall) | May 28 – Jul 5 |
| Carrots | Sow outdoors (spring) | May 24 – Jul 9 |
| Carrots | Sow outdoors (fall) | May 5 – Jun 20 |
| Garlic | Plant outdoors (fall) | Sep 4 – Oct 5 |
Where these dates come from
ZIP code 59213 is matched to the NOAA station Wolf Point 29 Ene, MT, 21.3 km away, at 2,085 ft elevation (126 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wolf Point 29 Ene, MT (used) | 2,085 ft | May 24 | Sep 14 |
| Culbertson, MT | 1,940 ft | May 21 | Sep 20 |
| Wolf Point 34 Ne, MT | 2,643 ft | May 13 | Sep 28 |
| Medicine Lake 3 Se, MT | 1,942 ft | May 16 | Sep 18 |
Frost dates near Brockton
- Poplar, MT 59255 · last May 24, first Sep 14
- Culbertson, MT 59218 · last May 21, first Sep 20
- Froid, MT 59226 · last May 16, first Sep 18
- Homestead, MT 59242 · last May 16, first Sep 18
- Medicine Lake, MT 59247 · last May 16, first Sep 18
- Reserve, MT 59258 · last May 25, first Sep 14
- Bainville, MT 59212 · last May 21, first Sep 20
- Lambert, MT 59243 · last May 11, first Sep 27
Frequently asked questions
- When is the last frost in Brockton, MT?
- For ZIP code 59213, the average last spring frost (32°F) is May 24, based on NOAA 1991-2020 climate normals for the Wolf Point 29 Ene, MT weather station. There is a 1-in-10 chance of a frost after June 6.
- When is the first frost in Brockton, MT?
- The average first fall frost (32°F) is September 14. There is a 1-in-10 chance of frost by September 1, so tender plants are at risk from that point on.
- How long is the growing season in 59213?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 110 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.