Frost dates for 59002Acton, MT
The average last spring frost in Acton is May 4 and the average first fall frost is October 7, giving a typical growing season of about 156 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 4
- Average first fall frost
- Oct 7
- Growing season
- 156 days
Safer after May 18 (1-in-10 risk)
Possible by Sep 26 (1-in-10 risk)
Last frost typically in 189 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 2 · May 15 · May 29 | Sep 16 · Sep 28 · Oct 12 | 135 days | 100% |
| Frost / freeze (32°F) | Apr 20 · May 4 · May 18 | Sep 26 · Oct 7 · Oct 21 | 156 days | 100% |
| Hard freeze (28°F) | Apr 4 · Apr 21 · May 7 | Oct 1 · Oct 16 · Oct 31 | 177 days | 100% |
Planting calendar for Acton
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 3 – Jun 9 |
| Tomatoes | Transplant outdoors | May 20 – Jun 17 |
| Peppers | Start seeds indoors | Apr 3 – May 4 |
| Peppers | Transplant outdoors | Jun 3 – Jul 4 |
| Eggplant | Start seeds indoors | Apr 20 – May 19 |
| Eggplant | Transplant outdoors | Jun 3 – Jul 4 |
| Cucumbers | Sow outdoors | Jun 3 – Jun 27 |
| Summer squash | Sow outdoors | May 20 – Jul 4 |
| Winter squash & pumpkins | Sow outdoors | Jun 3 – Jul 4 |
| Snap beans | Sow outdoors | May 20 – Jul 20 |
| Sweet corn | Sow outdoors | May 20 – Jun 17 |
| Watermelon & cantaloupe | Sow outdoors | Jun 3 – Jul 4 |
| Okra | Sow outdoors | May 27 – Jun 19 |
| Peas | Sow outdoors (spring) | Apr 3 – May 19 |
| Potatoes | Plant outdoors (spring) | Apr 3 – Jun 3 |
| Onions | Start seeds indoors (spring) | Feb 20 – Mar 19 |
| Onions | Transplant outdoors (spring) | Apr 20 – May 19 |
| Broccoli | Start seeds indoors (spring) | Mar 16 – Apr 19 |
| Broccoli | Transplant outdoors (spring) | Apr 20 – May 19 |
| Broccoli | Start seeds indoors (fall) | Jun 7 – Jun 17 |
| Broccoli | Transplant outdoors (fall) | Jul 7 – Jul 18 |
| Cabbage | Start seeds indoors (spring) | Mar 6 – Apr 3 |
| Cabbage | Transplant outdoors (spring) | Apr 3 – May 4 |
| Cabbage | Start seeds indoors (fall) | May 28 – Jun 27 |
| Cabbage | Transplant outdoors (fall) | Jun 27 – Jul 28 |
| Leaf lettuce | Sow outdoors (spring) | Apr 3 – Jun 19 |
| Leaf lettuce | Sow outdoors (fall) | Jun 27 – Aug 13 |
| Spinach | Sow outdoors (spring) | Mar 27 – May 10 |
| Spinach | Sow outdoors (fall) | Jul 14 – Aug 18 |
| Radishes | Sow outdoors (spring) | Apr 3 – May 24 |
| Radishes | Sow outdoors (fall) | Jun 27 – Aug 28 |
| Kale | Sow outdoors (spring) | Apr 20 – May 10 |
| Kale | Sow outdoors (fall) | Jun 20 – Jul 28 |
| Carrots | Sow outdoors (spring) | May 4 – Jun 19 |
| Carrots | Sow outdoors (fall) | May 28 – Jul 13 |
| Garlic | Plant outdoors (fall) | Sep 27 – Oct 28 |
Where these dates come from
ZIP code 59002 is matched to the NOAA station Billings Logan Intl Ap, MT, 17.7 km away, at 3,581 ft elevation (221 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Billings Logan Intl Ap, MT (used) | 3,581 ft | May 4 | Oct 7 |
| Billings Wfo, MT | 3,185 ft | May 5 | Oct 3 |
| Billings Wtp, MT | 3,097 ft | May 10 | Oct 1 |
| Huntley Exp Stn, MT | 3,034 ft | May 12 | Sep 25 |
Frost dates near Acton
- Billings, MT 59105 · last May 4, first Oct 7
- Broadview, MT 59015 · last May 22, first Sep 15
- Molt, MT 59057 · last May 24, first Sep 21
- Shepherd, MT 59079 · last May 12, first Sep 25
- Laurel, MT 59044 · last May 5, first Oct 3
- Huntley, MT 59037 · last May 12, first Sep 25
- Park City, MT 59063 · last May 27, first Sep 14
- Worden, MT 59088 · last May 12, first Sep 25
Frequently asked questions
- When is the last frost in Acton, MT?
- For ZIP code 59002, the average last spring frost (32°F) is May 4, based on NOAA 1991-2020 climate normals for the Billings Logan Intl Ap, MT weather station. There is a 1-in-10 chance of a frost after May 18.
- When is the first frost in Acton, MT?
- The average first fall frost (32°F) is October 7. There is a 1-in-10 chance of frost by September 26, so tender plants are at risk from that point on.
- How long is the growing season in 59002?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 156 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.