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🍂 First Frost Dates for Ravalli, Montana 59863

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 21. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Ravalli, 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% chancealways
20% chancealways
30% chancealways
40% chancealways
50% chancealways
60% chancealways
70% chancealways
80% chancealways
90% chancealways
Probability of light freeze (32°F) on or before...
10% chanceSep 13
20% chanceSep 18
30% chanceSep 21
40% chanceSep 24
50% chanceSep 27
60% chanceSep 29
70% chanceOct 1
80% chanceOct 4
90% chanceOct 7
Probability of moderate freeze (28°F) on or before...
10% chanceSep 23
20% chanceSep 28
30% chanceOct 1
40% chanceOct 3
50% chanceOct 6
60% chanceOct 8
70% chanceOct 11
80% chanceOct 15
90% chanceOct 20
Probability of moderate hard freeze (24°F) on or before...
10% chanceOct 2
20% chanceOct 7
30% chanceOct 12
40% chanceOct 16
50% chanceOct 19
60% chanceOct 22
70% chanceOct 25
80% chanceOct 29
90% chanceNov 3
Probability of hard freeze (20°F) on or before...
10% chanceOct 14
20% chanceOct 21
30% chanceOct 25
40% chanceOct 29
50% chanceNov 1
60% chanceNov 4
70% chanceNov 8
80% chanceNov 13
90% chanceNov 21
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 26
20% chanceNov 1
30% chanceNov 5
40% chanceNov 9
50% chanceNov 13
60% chanceNov 18
70% chanceNov 23
80% chanceNov 29
90% chanceDec 5

Agricultural climatic data from weather station: SAINT IGNATIUS (USC00247286)

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