A 36°F frost is always a risk here. (See detailed probabilities below.)
The last 32°F light freeze date is 30% likely to be on Jun 3. (See detailed probabilities below.)
(See also 🍂 First Fall Frost Dates.)
Last frost date probabilities for Simms, MT are based on historical climate data.
Always check your local forecast for the most up-to-date frost warnings.
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📚 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 | always |
| 20% chance | always |
| 30% chance | always |
| 40% chance | always |
| 50% chance | always |
| 60% chance | always |
| 70% chance | always |
| 80% chance | always |
| 90% chance | always |
| Probability of light freeze (32°F) on or after… | |
|---|---|
| 10% chance | Jun 13 |
| 20% chance | Jun 7 |
| 30% chance | Jun 3 |
| 40% chance | May 31 |
| 50% chance | May 29 |
| 60% chance | May 25 |
| 70% chance | May 22 |
| 80% chance | May 19 |
| 90% chance | May 14 |
| Probability of moderate freeze (28°F) on or after… | |
|---|---|
| 10% chance | May 27 |
| 20% chance | May 23 |
| 30% chance | May 19 |
| 40% chance | May 16 |
| 50% chance | May 13 |
| 60% chance | May 11 |
| 70% chance | May 8 |
| 80% chance | May 4 |
| 90% chance | Apr 30 |
| Probability of moderate hard freeze (24°F) on or after… | |
|---|---|
| 10% chance | May 15 |
| 20% chance | May 10 |
| 30% chance | May 7 |
| 40% chance | May 4 |
| 50% chance | May 2 |
| 60% chance | Apr 29 |
| 70% chance | Apr 26 |
| 80% chance | Apr 22 |
| 90% chance | Apr 16 |
| Probability of hard freeze (20°F) on or after… | |
|---|---|
| 10% chance | May 5 |
| 20% chance | Apr 30 |
| 30% chance | Apr 27 |
| 40% chance | Apr 23 |
| 50% chance | Apr 20 |
| 60% chance | Apr 16 |
| 70% chance | Apr 12 |
| 80% chance | Apr 8 |
| 90% chance | Apr 3 |
| Probability of severe hard freeze (16°F) on or after… | |
|---|---|
| 10% chance | Apr 28 |
| 20% chance | Apr 22 |
| 30% chance | Apr 17 |
| 40% chance | Apr 13 |
| 50% chance | Apr 9 |
| 60% chance | Apr 6 |
| 70% chance | Apr 3 |
| 80% chance | Mar 31 |
| 90% chance | Mar 25 |
Agricultural climatic data from weather station: SUN RIVER 4 S (USC00248021)