Frost dates for 59079Shepherd, MT
The average last spring frost in Shepherd is May 12 and the average first fall frost is September 25, giving a typical growing season of about 136 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Sep 25
- Growing season
- 136 days
Safer after May 26 (1-in-10 risk)
Possible by Sep 13 (1-in-10 risk)
Last frost typically in 197 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 13 · May 25 · Jun 10 | Sep 1 · Sep 14 · Sep 29 | 111 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 12 · May 26 | Sep 13 · Sep 25 · Oct 8 | 136 days | 100% |
| Hard freeze (28°F) | Apr 15 · Apr 30 · May 14 | Sep 23 · Oct 4 · Oct 18 | 157 days | 100% |
Planting calendar for Shepherd
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 5 |
| 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 15 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 8 |
| Sweet corn | Sow outdoors | May 28 – Jun 5 |
| 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 26 – Jun 5 |
| Broccoli | Transplant outdoors (fall) | Jun 25 – Jul 6 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 16 – Jun 15 |
| Cabbage | Transplant outdoors (fall) | Jun 15 – Jul 16 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 15 – Aug 1 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 2 – Aug 6 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 15 – Aug 16 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 8 – Jul 16 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 16 – Jul 1 |
| Garlic | Plant outdoors (fall) | Sep 15 – Oct 16 |
Where these dates come from
ZIP code 59079 is matched to the NOAA station Huntley Exp Stn, MT, 8 km away, at 3,034 ft elevation (73 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Huntley Exp Stn, MT (used) | 3,034 ft | May 12 | Sep 25 |
| Billings Logan Intl Ap, MT | 3,581 ft | May 4 | Oct 7 |
| Billings Wtp, MT | 3,097 ft | May 10 | Oct 1 |
| Billings Wfo, MT | 3,185 ft | May 5 | Oct 3 |
Frost dates near Shepherd
- Huntley, MT 59037 · last May 12, first Sep 25
- Billings, MT 59107 · last May 10, first Oct 1
- Worden, MT 59088 · last May 12, first Sep 25
- Ballantine, MT 59006 · last May 12, first Sep 25
- Acton, MT 59002 · last May 4, first Oct 7
- Pompeys Pillar, MT 59064 · last May 12, first Sep 25
- Broadview, MT 59015 · last May 22, first Sep 15
- Laurel, MT 59044 · last May 5, first Oct 3
Frequently asked questions
- When is the last frost in Shepherd, MT?
- For ZIP code 59079, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Huntley Exp Stn, MT weather station. There is a 1-in-10 chance of a frost after May 26.
- When is the first frost in Shepherd, MT?
- The average first fall frost (32°F) is September 25. There is a 1-in-10 chance of frost by September 13, so tender plants are at risk from that point on.
- How long is the growing season in 59079?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 136 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.