The last 36°F Spring frost date is 30% likely to be on Jun 1. (See detailed probabilities below.)
The last 32°F light freeze date is 30% likely to be on May 18. (See detailed probabilities below.)
(See also 🍂 First Fall Frost Dates.)
Last frost date probabilities for Colstrip, MT are based on historical climate data.
Always check your local forecast for the most up-to-date frost warnings.
Book Recommendations (ads!)
📚 Growing Under Cover: Techniques for a More Productive, Weather-Resistant, Pest-Free Vegetable Garden
The last spring frost signals when your area is safe from freezing temperatures. Tender plants can now grow outdoors without cold damage! This marks the beginning of the growing season. Last spring frost serves as your essential starting point for planting warm-season crops. It's also time to remove winter protection from your perennials. Enjoy the longer days and warmer weather!
Start seeds indoors several weeks before your last frost date. This gives plants time to reach transplanting size when weather permits. Plan your outdoor planting schedule around your area's average last frost date. Plant some crops before and some after this date to protect against weather changes. Look for spots in your yard where frost stays longer or disappears earlier. Create your own frost map to use all available growing space and extend your season. Keep watching your local weather forecast to catch any surprise late frosts.
| Probability of frost (36°F) on or after… | |
|---|---|
| 10% chance | Jun 11 |
| 20% chance | Jun 5 |
| 30% chance | Jun 1 |
| 40% chance | May 29 |
| 50% chance | May 26 |
| 60% chance | May 23 |
| 70% chance | May 19 |
| 80% chance | May 16 |
| 90% chance | May 12 |
| Probability of light freeze (32°F) on or after… | |
|---|---|
| 10% chance | May 27 |
| 20% chance | May 22 |
| 30% chance | May 18 |
| 40% chance | May 15 |
| 50% chance | May 12 |
| 60% chance | May 10 |
| 70% chance | May 7 |
| 80% chance | May 3 |
| 90% chance | Apr 30 |
| Probability of moderate freeze (28°F) on or after… | |
|---|---|
| 10% chance | May 14 |
| 20% chance | May 10 |
| 30% chance | May 7 |
| 40% chance | May 4 |
| 50% chance | May 1 |
| 60% chance | Apr 29 |
| 70% chance | Apr 25 |
| 80% chance | Apr 21 |
| 90% chance | Apr 16 |
| Probability of moderate hard freeze (24°F) on or after… | |
|---|---|
| 10% chance | May 6 |
| 20% chance | Apr 30 |
| 30% chance | Apr 26 |
| 40% chance | Apr 22 |
| 50% chance | Apr 19 |
| 60% chance | Apr 16 |
| 70% chance | Apr 12 |
| 80% chance | Apr 9 |
| 90% chance | Apr 4 |
| Probability of hard freeze (20°F) on or after… | |
|---|---|
| 10% chance | Apr 27 |
| 20% chance | Apr 21 |
| 30% chance | Apr 16 |
| 40% chance | Apr 12 |
| 50% chance | Apr 8 |
| 60% chance | Apr 5 |
| 70% chance | Apr 2 |
| 80% chance | Mar 30 |
| 90% chance | Mar 22 |
| Probability of severe hard freeze (16°F) on or after… | |
|---|---|
| 10% chance | Apr 17 |
| 20% chance | Apr 10 |
| 30% chance | Apr 5 |
| 40% chance | Apr 2 |
| 50% chance | Mar 30 |
| 60% chance | Mar 25 |
| 70% chance | Mar 21 |
| 80% chance | Mar 15 |
| 90% chance | Mar 7 |
Agricultural climatic data from weather station: COLSTRIP (USC00241905)