🍂 2026 First Frost Dates for Roscoe, Montana 59071
A 36°F frost is always a risk here. (See detailed probabilities below.)
The first 32°F light freeze date is 30% likely to be on Sep 8. (See detailed probabilities below.)
(See also 🌷 Last Spring Frost Dates.)
First frost date probabilities for Roscoe, MT are based on historical climate data.
Always check your local forecast for the most up-to-date frost warnings.
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What is a First Frost Date?
The first fall frost signals the end of your local growing season. This date serves as an important deadline for gardeners and farmers. You'll need to complete harvesting before this point. Annuals and other tender plants will die back when frost hits, and perennial plants will enter their dormant phase for winter. Meanwhile, it's time to enjoy a cup of hot cocoa and a cozy sweater—and start planning your spring garden!
How to use the First Frost Date?
Watch your local weather forecasts in early fall to predict the first frost date. Harvest tender crops and protect vulnerable plants before frost arrives. For late-summer plantings, count backward from your area's average first frost date. This ensures your crops have enough time to mature. Keep track of when frost actually occurs in your garden each year. This helps you identify protected spots where the growing season might last longer.
First Frost Date Probabilities
| Probability of frost (36°F) on or before... | |
|---|---|
| 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 before... | |
|---|---|
| 10% chance | Aug 31 |
| 20% chance | Sep 5 |
| 30% chance | Sep 8 |
| 40% chance | Sep 11 |
| 50% chance | Sep 14 |
| 60% chance | Sep 18 |
| 70% chance | Sep 21 |
| 80% chance | Sep 24 |
| 90% chance | Sep 28 |
| Probability of moderate freeze (28°F) on or before... | |
|---|---|
| 10% chance | Sep 7 |
| 20% chance | Sep 12 |
| 30% chance | Sep 18 |
| 40% chance | Sep 22 |
| 50% chance | Sep 25 |
| 60% chance | Sep 28 |
| 70% chance | Oct 1 |
| 80% chance | Oct 4 |
| 90% chance | Oct 10 |
| Probability of moderate hard freeze (24°F) on or before... | |
|---|---|
| 10% chance | Sep 15 |
| 20% chance | Sep 23 |
| 30% chance | Sep 28 |
| 40% chance | Oct 1 |
| 50% chance | Oct 4 |
| 60% chance | Oct 7 |
| 70% chance | Oct 11 |
| 80% chance | Oct 16 |
| 90% chance | Oct 22 |
| Probability of hard freeze (20°F) on or before... | |
|---|---|
| 10% chance | Sep 23 |
| 20% chance | Oct 1 |
| 30% chance | Oct 5 |
| 40% chance | Oct 8 |
| 50% chance | Oct 13 |
| 60% chance | Oct 17 |
| 70% chance | Oct 21 |
| 80% chance | Oct 26 |
| 90% chance | Nov 2 |
| Probability of severe hard freeze (16°F) on or before... | |
|---|---|
| 10% chance | Oct 1 |
| 20% chance | Oct 8 |
| 30% chance | Oct 13 |
| 40% chance | Oct 17 |
| 50% chance | Oct 22 |
| 60% chance | Oct 27 |
| 70% chance | Oct 31 |
| 80% chance | Nov 4 |
| 90% chance | Nov 10 |
Agricultural climatic data from weather station: MYSTIC LAKE (USC00245961:frost)