Frost dates for 59106Billings, MT
The average last spring frost in Billings is May 5 and the average first fall frost is October 3, giving a typical growing season of about 149 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 5
- Average first fall frost
- Oct 3
- Growing season
- 149 days
Safer after May 21 (1-in-10 risk)
Possible by Sep 20 (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 6 · May 19 · Jun 2 | Sep 9 · Sep 23 · Oct 5 | 125 days | 100% |
| Frost / freeze (32°F) | Apr 23 · May 5 · May 21 | Sep 20 · Oct 3 · Oct 17 | 149 days | 100% |
| Hard freeze (28°F) | Apr 7 · Apr 23 · May 6 | Sep 29 · Oct 14 · Oct 27 | 172 days | 100% |
Planting calendar for Billings
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 4 – Jun 10 |
| Tomatoes | Transplant outdoors | May 21 – Jun 13 |
| Peppers | Start seeds indoors | Apr 4 – May 5 |
| Peppers | Transplant outdoors | Jun 4 – Jul 5 |
| Eggplant | Start seeds indoors | Apr 21 – May 20 |
| Eggplant | Transplant outdoors | Jun 4 – Jul 5 |
| Cucumbers | Sow outdoors | Jun 4 – Jun 23 |
| Summer squash | Sow outdoors | May 21 – Jul 5 |
| Winter squash & pumpkins | Sow outdoors | Jun 4 – Jul 5 |
| Snap beans | Sow outdoors | May 21 – Jul 16 |
| Sweet corn | Sow outdoors | May 21 – Jun 13 |
| Watermelon & cantaloupe | Sow outdoors | Jun 4 – Jul 5 |
| Okra | Sow outdoors | May 28 – Jun 20 |
| Peas | Sow outdoors (spring) | Apr 4 – May 20 |
| Potatoes | Plant outdoors (spring) | Apr 4 – Jun 4 |
| Onions | Start seeds indoors (spring) | Feb 21 – Mar 20 |
| Onions | Transplant outdoors (spring) | Apr 21 – May 20 |
| Broccoli | Start seeds indoors (spring) | Mar 17 – Apr 20 |
| Broccoli | Transplant outdoors (spring) | Apr 21 – May 20 |
| Broccoli | Start seeds indoors (fall) | Jun 3 – Jun 13 |
| Broccoli | Transplant outdoors (fall) | Jul 3 – Jul 14 |
| Cabbage | Start seeds indoors (spring) | Mar 7 – Apr 4 |
| Cabbage | Transplant outdoors (spring) | Apr 4 – May 5 |
| Cabbage | Start seeds indoors (fall) | May 24 – Jun 23 |
| Cabbage | Transplant outdoors (fall) | Jun 23 – Jul 24 |
| Leaf lettuce | Sow outdoors (spring) | Apr 4 – Jun 20 |
| Leaf lettuce | Sow outdoors (fall) | Jun 23 – Aug 9 |
| Spinach | Sow outdoors (spring) | Mar 28 – May 11 |
| Spinach | Sow outdoors (fall) | Jul 10 – Aug 14 |
| Radishes | Sow outdoors (spring) | Apr 4 – May 25 |
| Radishes | Sow outdoors (fall) | Jun 23 – Aug 24 |
| Kale | Sow outdoors (spring) | Apr 21 – May 11 |
| Kale | Sow outdoors (fall) | Jun 16 – Jul 24 |
| Carrots | Sow outdoors (spring) | May 5 – Jun 20 |
| Carrots | Sow outdoors (fall) | May 24 – Jul 9 |
| Garlic | Plant outdoors (fall) | Sep 23 – Oct 24 |
Where these dates come from
ZIP code 59106 is matched to the NOAA station Billings Wfo, MT, 7 km away, at 3,185 ft elevation (115 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Billings Wfo, MT (used) | 3,185 ft | May 5 | Oct 3 |
| Billings Logan Intl Ap, MT | 3,581 ft | May 4 | Oct 7 |
| Billings Wtp, MT | 3,097 ft | May 10 | Oct 1 |
| Huntley Exp Stn, MT | 3,034 ft | May 12 | Sep 25 |
Frost dates near Billings
- Billings, MT 59102 · last May 5, first Oct 3
- Laurel, MT 59044 · last May 5, first Oct 3
- Acton, MT 59002 · last May 4, first Oct 7
- Molt, MT 59057 · last May 24, first Sep 21
- Park City, MT 59063 · last May 27, first Sep 14
- Shepherd, MT 59079 · last May 12, first Sep 25
- Huntley, MT 59037 · last May 12, first Sep 25
- Broadview, MT 59015 · last May 22, first Sep 15
Frequently asked questions
- When is the last frost in Billings, MT?
- For ZIP code 59106, the average last spring frost (32°F) is May 5, based on NOAA 1991-2020 climate normals for the Billings Wfo, MT weather station. There is a 1-in-10 chance of a frost after May 21.
- When is the first frost in Billings, MT?
- The average first fall frost (32°F) is October 3. There is a 1-in-10 chance of frost by September 20, so tender plants are at risk from that point on.
- How long is the growing season in 59106?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 149 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.