Frost dates for 59019Columbus, MT
The average last spring frost in Columbus is May 27 and the average first fall frost is September 14, giving a typical growing season of about 108 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 27
- Average first fall frost
- Sep 14
- Growing season
- 108 days
Safer after Jun 12 (1-in-10 risk)
Possible by Sep 1 (1-in-10 risk)
Last frost typically in 205 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 27 · Jun 12 · Jul 3 | Aug 18 · Sep 2 · Sep 15 | 79 days | 100% |
| Frost / freeze (32°F) | May 14 · May 27 · Jun 12 | Sep 1 · Sep 14 · Sep 28 | 108 days | 100% |
| Hard freeze (28°F) | Apr 30 · May 13 · May 27 | Sep 11 · Sep 26 · Oct 9 | 134 days | 100% |
Planting calendar for Columbus
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 26 – Jul 2 |
| Tomatoes | Transplant outdoors | Jun 12 – May 25 |
| Peppers | Start seeds indoors | Apr 26 – May 27 |
| Peppers | Transplant outdoors | Jun 26 – Jul 27 |
| Eggplant | Start seeds indoors | May 13 – Jun 11 |
| Eggplant | Transplant outdoors | Jun 26 – Jul 27 |
| Cucumbers | Sow outdoors | Jun 26 – Jun 4 |
| Summer squash | Sow outdoors | Jun 12 – Jul 27 |
| Winter squash & pumpkins | Sow outdoors | Jun 26 – Jul 27 |
| Snap beans | Sow outdoors | Jun 12 – Jun 27 |
| Sweet corn | Sow outdoors | Jun 12 – May 25 |
| Watermelon & cantaloupe | Sow outdoors | Jun 26 – Jul 27 |
| Okra | Sow outdoors | Jun 19 – Jul 12 |
| Peas | Sow outdoors (spring) | Apr 26 – Jun 11 |
| Potatoes | Plant outdoors (spring) | Apr 26 – Jun 26 |
| Onions | Start seeds indoors (spring) | Mar 15 – Apr 11 |
| Onions | Transplant outdoors (spring) | May 13 – Jun 11 |
| Broccoli | Start seeds indoors (spring) | Apr 8 – May 12 |
| Broccoli | Transplant outdoors (spring) | May 13 – Jun 11 |
| Broccoli | Start seeds indoors (fall) | May 15 – May 25 |
| Broccoli | Transplant outdoors (fall) | Jun 14 – Jun 25 |
| Cabbage | Start seeds indoors (spring) | Mar 29 – Apr 26 |
| Cabbage | Transplant outdoors (spring) | Apr 26 – May 27 |
| Cabbage | Start seeds indoors (fall) | May 5 – Jun 4 |
| Cabbage | Transplant outdoors (fall) | Jun 4 – Jul 5 |
| Leaf lettuce | Sow outdoors (spring) | Apr 26 – Jul 12 |
| Leaf lettuce | Sow outdoors (fall) | Jun 4 – Jul 21 |
| Spinach | Sow outdoors (spring) | Apr 19 – Jun 2 |
| Spinach | Sow outdoors (fall) | Jun 21 – Jul 26 |
| Radishes | Sow outdoors (spring) | Apr 26 – Jun 16 |
| Radishes | Sow outdoors (fall) | Jun 4 – Aug 5 |
| Kale | Sow outdoors (spring) | May 13 – Jun 2 |
| Kale | Sow outdoors (fall) | May 28 – Jul 5 |
| Carrots | Sow outdoors (spring) | May 27 – Jul 12 |
| Carrots | Sow outdoors (fall) | May 5 – Jun 20 |
| Garlic | Plant outdoors (fall) | Sep 4 – Oct 5 |
Where these dates come from
ZIP code 59019 is matched to the NOAA station Columbus, MT, 2.2 km away, at 3,602 ft elevation (26 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Columbus, MT (used) | 3,602 ft | May 27 | Sep 14 |
| Joliet, MT | 3,838 ft | May 29 | Sep 15 |
| Rapelje, MT | 4,068 ft | May 24 | Sep 21 |
| Bridger 2 N, MT | 3,583 ft | May 14 | Sep 24 |
Frost dates near Columbus
- Absarokee, MT 59001 · last Jun 1, first Sep 11
- Boyd, MT 59013 · last May 29, first Sep 15
- Reed Point, MT 59069 · last May 24, first Sep 21
- Joliet, MT 59041 · last May 29, first Sep 15
- Park City, MT 59063 · last May 27, first Sep 14
- Roberts, MT 59070 · last May 29, first Sep 15
- Molt, MT 59057 · last May 24, first Sep 21
- Fishtail, MT 59028 · last Jun 3, first Sep 19
Frequently asked questions
- When is the last frost in Columbus, MT?
- For ZIP code 59019, the average last spring frost (32°F) is May 27, based on NOAA 1991-2020 climate normals for the Columbus, MT weather station. There is a 1-in-10 chance of a frost after June 12.
- When is the first frost in Columbus, MT?
- The average first fall frost (32°F) is September 14. There is a 1-in-10 chance of frost by September 1, so tender plants are at risk from that point on.
- How long is the growing season in 59019?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 108 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.