Frost dates for 59214Brockway, MT
The average last spring frost in Brockway is May 20 and the average first fall frost is September 19, giving a typical growing season of about 121 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 20
- Average first fall frost
- Sep 19
- Growing season
- 121 days
Safer after Jun 5 (1-in-10 risk)
Possible by Sep 4 (1-in-10 risk)
Last frost typically in 198 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 31 · Jun 17 | Aug 23 · Sep 8 · Sep 22 | 100 days | 100% |
| Frost / freeze (32°F) | May 6 · May 20 · Jun 5 | Sep 4 · Sep 19 · Oct 2 | 121 days | 100% |
| Hard freeze (28°F) | Apr 26 · May 9 · May 23 | Sep 13 · Sep 28 · Oct 11 | 141 days | 100% |
Planting calendar for Brockway
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 19 – Jun 25 |
| Tomatoes | Transplant outdoors | Jun 5 – May 30 |
| Peppers | Start seeds indoors | Apr 19 – May 20 |
| Peppers | Transplant outdoors | Jun 19 – Jul 20 |
| Eggplant | Start seeds indoors | May 6 – Jun 4 |
| Eggplant | Transplant outdoors | Jun 19 – Jul 20 |
| Cucumbers | Sow outdoors | Jun 19 – Jun 9 |
| Summer squash | Sow outdoors | Jun 5 – Jul 20 |
| Winter squash & pumpkins | Sow outdoors | Jun 19 – Jul 20 |
| Snap beans | Sow outdoors | Jun 5 – Jul 2 |
| Sweet corn | Sow outdoors | Jun 5 – May 30 |
| Watermelon & cantaloupe | Sow outdoors | Jun 19 – Jul 20 |
| Okra | Sow outdoors | Jun 12 – Jul 5 |
| Peas | Sow outdoors (spring) | Apr 19 – Jun 4 |
| Potatoes | Plant outdoors (spring) | Apr 19 – Jun 19 |
| Onions | Start seeds indoors (spring) | Mar 8 – Apr 4 |
| Onions | Transplant outdoors (spring) | May 6 – Jun 4 |
| Broccoli | Start seeds indoors (spring) | Apr 1 – May 5 |
| Broccoli | Transplant outdoors (spring) | May 6 – Jun 4 |
| Broccoli | Start seeds indoors (fall) | May 20 – May 30 |
| Broccoli | Transplant outdoors (fall) | Jun 19 – Jun 30 |
| Cabbage | Start seeds indoors (spring) | Mar 22 – Apr 19 |
| Cabbage | Transplant outdoors (spring) | Apr 19 – May 20 |
| Cabbage | Start seeds indoors (fall) | May 10 – Jun 9 |
| Cabbage | Transplant outdoors (fall) | Jun 9 – Jul 10 |
| Leaf lettuce | Sow outdoors (spring) | Apr 19 – Jul 5 |
| Leaf lettuce | Sow outdoors (fall) | Jun 9 – Jul 26 |
| Spinach | Sow outdoors (spring) | Apr 12 – May 26 |
| Spinach | Sow outdoors (fall) | Jun 26 – Jul 31 |
| Radishes | Sow outdoors (spring) | Apr 19 – Jun 9 |
| Radishes | Sow outdoors (fall) | Jun 9 – Aug 10 |
| Kale | Sow outdoors (spring) | May 6 – May 26 |
| Kale | Sow outdoors (fall) | Jun 2 – Jul 10 |
| Carrots | Sow outdoors (spring) | May 20 – Jul 5 |
| Carrots | Sow outdoors (fall) | May 10 – Jun 25 |
| Garlic | Plant outdoors (fall) | Sep 9 – Oct 10 |
Where these dates come from
ZIP code 59214 is matched to the NOAA station Brockway 3 Wsw, MT, 5.9 km away, at 2,630 ft elevation (70 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Brockway 3 Wsw, MT (used) | 2,630 ft | May 20 | Sep 19 |
| Circle, MT | 2,480 ft | May 17 | Sep 22 |
| Terry 21 Nnw, MT | 3,142 ft | May 26 | Sep 17 |
| Rock Springs, MT | 3,024 ft | May 15 | Sep 25 |
Frost dates near Brockway
- Circle, MT 59215 · last May 17, first Sep 22
- Lindsay, MT 59339 · last May 26, first Sep 17
- Terry, MT 59349 · last May 12, first Sep 28
- Cohagen, MT 59322 · last May 25, first Sep 14
- Bloomfield, MT 59315 · last May 17, first Sep 22
- Angela, MT 59312 · last May 15, first Sep 25
- Vida, MT 59274 · last May 16, first Sep 22
- Richey, MT 59259 · last May 16, first Sep 22
Frequently asked questions
- When is the last frost in Brockway, MT?
- For ZIP code 59214, the average last spring frost (32°F) is May 20, based on NOAA 1991-2020 climate normals for the Brockway 3 Wsw, MT weather station. There is a 1-in-10 chance of a frost after June 5.
- When is the first frost in Brockway, MT?
- The average first fall frost (32°F) is September 19. There is a 1-in-10 chance of frost by September 4, so tender plants are at risk from that point on.
- How long is the growing season in 59214?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 121 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.