Frost dates for 59248Nashua, MT
The average last spring frost in Nashua is May 12 and the average first fall frost is September 24, giving a typical growing season of about 134 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Sep 24
- Growing season
- 134 days
Safer after May 26 (1-in-10 risk)
Possible by Sep 12 (1-in-10 risk)
Last frost typically in 190 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 10 · May 23 · Jun 5 | Sep 4 · Sep 16 · Sep 28 | 116 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 12 · May 26 | Sep 12 · Sep 24 · Oct 6 | 134 days | 100% |
| Hard freeze (28°F) | Apr 17 · May 1 · May 16 | Sep 19 · Oct 2 · Oct 16 | 153 days | 100% |
Planting calendar for Nashua
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 11 – Jun 17 |
| Tomatoes | Transplant outdoors | May 28 – Jun 4 |
| Peppers | Start seeds indoors | Apr 11 – May 12 |
| Peppers | Transplant outdoors | Jun 11 – Jul 12 |
| Eggplant | Start seeds indoors | Apr 28 – May 27 |
| Eggplant | Transplant outdoors | Jun 11 – Jul 12 |
| Cucumbers | Sow outdoors | Jun 11 – Jun 14 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 7 |
| Sweet corn | Sow outdoors | May 28 – Jun 4 |
| Watermelon & cantaloupe | Sow outdoors | Jun 11 – Jul 12 |
| Okra | Sow outdoors | Jun 4 – Jun 27 |
| Peas | Sow outdoors (spring) | Apr 11 – May 27 |
| Potatoes | Plant outdoors (spring) | Apr 11 – Jun 11 |
| Onions | Start seeds indoors (spring) | Feb 28 – Mar 27 |
| Onions | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (spring) | Mar 24 – Apr 27 |
| Broccoli | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (fall) | May 25 – Jun 4 |
| Broccoli | Transplant outdoors (fall) | Jun 24 – Jul 5 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 15 – Jun 14 |
| Cabbage | Transplant outdoors (fall) | Jun 14 – Jul 15 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 14 – Jul 31 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 1 – Aug 5 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 14 – Aug 15 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 7 – Jul 15 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 15 – Jun 30 |
| Garlic | Plant outdoors (fall) | Sep 14 – Oct 15 |
Where these dates come from
ZIP code 59248 is matched to the NOAA station Nashua #2, MT, 0.2 km away, at 2,067 ft elevation (3 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Nashua #2, MT (used) | 2,067 ft | May 12 | Sep 24 |
| Ft Peck Pwr Plt, MT | 2,071 ft | May 8 | Oct 1 |
| Glasgow Intl Ap, MT | 2,285 ft | May 6 | Sep 30 |
| Glasgow #2, MT | 2,090 ft | May 3 | Oct 1 |
Frost dates near Nashua
- Fort Peck, MT 59223 · last May 8, first Oct 1
- Glasgow, MT 59230 · last May 6, first Sep 30
- Frazer, MT 59225 · last May 13, first Sep 27
- Saint Marie, MT 59231 · last May 13, first Sep 27
- Vandalia, MT 59273 · last May 3, first Oct 1
- Larslan, MT 59244 · last Jun 5, first Sep 2
- Wolf Point, MT 59201 · last May 8, first Sep 28
- Hinsdale, MT 59241 · last May 15, first Sep 23
Frequently asked questions
- When is the last frost in Nashua, MT?
- For ZIP code 59248, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Nashua #2, MT weather station. There is a 1-in-10 chance of a frost after May 26.
- When is the first frost in Nashua, MT?
- The average first fall frost (32°F) is September 24. There is a 1-in-10 chance of frost by September 12, so tender plants are at risk from that point on.
- How long is the growing season in 59248?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 134 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.