Frost dates for 59345Powderville, MT
The average last spring frost in Powderville is May 13 and the average first fall frost is September 25, giving a typical growing season of about 132 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 13
- Average first fall frost
- Sep 25
- Growing season
- 132 days
Safer after May 31 (1-in-10 risk)
Possible by Sep 6 (1-in-10 risk)
Last frost typically in 192 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 11 · May 24 · Jun 14 | Sep 1 · Sep 16 · Oct 1 | 112 days | 100% |
| Frost / freeze (32°F) | May 1 · May 13 · May 31 | Sep 6 · Sep 25 · Oct 9 | 132 days | 100% |
| Hard freeze (28°F) | Apr 18 · May 2 · May 22 | Sep 17 · Oct 4 · Oct 19 | 152 days | 100% |
Planting calendar for Powderville
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 12 – Jun 18 |
| Tomatoes | Transplant outdoors | May 29 – Jun 5 |
| Peppers | Start seeds indoors | Apr 12 – May 13 |
| Peppers | Transplant outdoors | Jun 12 – Jul 13 |
| Eggplant | Start seeds indoors | Apr 29 – May 28 |
| Eggplant | Transplant outdoors | Jun 12 – Jul 13 |
| Cucumbers | Sow outdoors | Jun 12 – Jun 15 |
| Summer squash | Sow outdoors | May 29 – Jul 13 |
| Winter squash & pumpkins | Sow outdoors | Jun 12 – Jul 13 |
| Snap beans | Sow outdoors | May 29 – Jul 8 |
| Sweet corn | Sow outdoors | May 29 – Jun 5 |
| Watermelon & cantaloupe | Sow outdoors | Jun 12 – Jul 13 |
| Okra | Sow outdoors | Jun 5 – Jun 28 |
| Peas | Sow outdoors (spring) | Apr 12 – May 28 |
| Potatoes | Plant outdoors (spring) | Apr 12 – Jun 12 |
| Onions | Start seeds indoors (spring) | Mar 1 – Mar 28 |
| Onions | Transplant outdoors (spring) | Apr 29 – May 28 |
| Broccoli | Start seeds indoors (spring) | Mar 25 – Apr 28 |
| Broccoli | Transplant outdoors (spring) | Apr 29 – May 28 |
| Broccoli | Start seeds indoors (fall) | May 26 – Jun 5 |
| Broccoli | Transplant outdoors (fall) | Jun 25 – Jul 6 |
| Cabbage | Start seeds indoors (spring) | Mar 15 – Apr 12 |
| Cabbage | Transplant outdoors (spring) | Apr 12 – May 13 |
| Cabbage | Start seeds indoors (fall) | May 16 – Jun 15 |
| Cabbage | Transplant outdoors (fall) | Jun 15 – Jul 16 |
| Leaf lettuce | Sow outdoors (spring) | Apr 12 – Jun 28 |
| Leaf lettuce | Sow outdoors (fall) | Jun 15 – Aug 1 |
| Spinach | Sow outdoors (spring) | Apr 5 – May 19 |
| Spinach | Sow outdoors (fall) | Jul 2 – Aug 6 |
| Radishes | Sow outdoors (spring) | Apr 12 – Jun 2 |
| Radishes | Sow outdoors (fall) | Jun 15 – Aug 16 |
| Kale | Sow outdoors (spring) | Apr 29 – May 19 |
| Kale | Sow outdoors (fall) | Jun 8 – Jul 16 |
| Carrots | Sow outdoors (spring) | May 13 – Jun 28 |
| Carrots | Sow outdoors (fall) | May 16 – Jul 1 |
| Garlic | Plant outdoors (fall) | Sep 15 – Oct 16 |
Where these dates come from
ZIP code 59345 is matched to the NOAA station Powderville 8 Nne, MT, 12.1 km away, at 2,800 ft elevation (28 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Powderville 8 Nne, MT (used) | 2,800 ft | May 13 | Sep 25 |
| Broadus, MT | 3,032 ft | May 16 | Sep 28 |
| Ekalaka, MT | 3,432 ft | May 20 | Sep 23 |
| Ridgeway 1 S, MT | 3,316 ft | May 17 | Sep 22 |
Frost dates near Powderville
- Olive, MT 59343 · last May 16, first Sep 28
- Volborg, MT 59351 · last May 16, first Sep 28
- Ekalaka, MT 59324 · last May 20, first Sep 23
- Hammond, MT 59332 · last May 17, first Sep 22
- Boyes, MT 59316 · last May 16, first Sep 28
- Broadus, MT 59317 · last May 14, first Sep 28
- Ismay, MT 59336 · last May 22, first Sep 15
- Willard, MT 59354 · last May 16, first Sep 26
Frequently asked questions
- When is the last frost in Powderville, MT?
- For ZIP code 59345, the average last spring frost (32°F) is May 13, based on NOAA 1991-2020 climate normals for the Powderville 8 Nne, MT weather station. There is a 1-in-10 chance of a frost after May 31.
- When is the first frost in Powderville, MT?
- The average first fall frost (32°F) is September 25. There is a 1-in-10 chance of frost by September 6, so tender plants are at risk from that point on.
- How long is the growing season in 59345?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 132 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.