The last 36°F Spring frost date is 30% likely to be on Jun 10. (See detailed probabilities below.)
The last 32°F light freeze date is 30% likely to be on May 20. (See detailed probabilities below.)
(See also 🍂 First Fall Frost Dates.)
Last frost date probabilities for Plains, MT are based on historical climate data.
Always check your local forecast for the most up-to-date frost warnings.
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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 22 |
| 20% chance | Jun 15 |
| 30% chance | Jun 10 |
| 40% chance | Jun 5 |
| 50% chance | Jun 1 |
| 60% chance | May 30 |
| 70% chance | May 27 |
| 80% chance | May 23 |
| 90% chance | May 17 |
| Probability of light freeze (32°F) on or after… | |
|---|---|
| 10% chance | May 29 |
| 20% chance | May 24 |
| 30% chance | May 20 |
| 40% chance | May 17 |
| 50% chance | May 14 |
| 60% chance | May 11 |
| 70% chance | May 8 |
| 80% chance | May 5 |
| 90% chance | May 1 |
| Probability of moderate freeze (28°F) on or after… | |
|---|---|
| 10% chance | May 12 |
| 20% chance | May 8 |
| 30% chance | May 5 |
| 40% chance | May 2 |
| 50% chance | Apr 30 |
| 60% chance | Apr 27 |
| 70% chance | Apr 24 |
| 80% chance | Apr 21 |
| 90% chance | Apr 17 |
| Probability of moderate hard freeze (24°F) on or after… | |
|---|---|
| 10% chance | Apr 29 |
| 20% chance | Apr 24 |
| 30% chance | Apr 20 |
| 40% chance | Apr 17 |
| 50% chance | Apr 13 |
| 60% chance | Apr 9 |
| 70% chance | Apr 5 |
| 80% chance | Mar 31 |
| 90% chance | Mar 27 |
| Probability of hard freeze (20°F) on or after… | |
|---|---|
| 10% chance | Apr 13 |
| 20% chance | Apr 6 |
| 30% chance | Apr 1 |
| 40% chance | Mar 30 |
| 50% chance | Mar 26 |
| 60% chance | Mar 22 |
| 70% chance | Mar 17 |
| 80% chance | Mar 11 |
| 90% chance | Mar 4 |
| Probability of severe hard freeze (16°F) on or after… | |
|---|---|
| 10% chance | Mar 28 |
| 20% chance | Mar 21 |
| 30% chance | Mar 17 |
| 40% chance | Mar 13 |
| 50% chance | Mar 8 |
| 60% chance | Mar 4 |
| 70% chance | Mar 1 |
| 80% chance | Feb 23 |
| 90% chance | Feb 13 |
Agricultural climatic data from weather station: HOT SPRINGS (USC00244297)