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🍂 First Frost Dates for Bigfork, Montana 59911

The first 36°F frost date is 30% likely to be on Sep 26. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Oct 6. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Bigfork, 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% chanceSep 17
20% chanceSep 22
30% chanceSep 26
40% chanceSep 29
50% chanceOct 1
60% chanceOct 3
70% chanceOct 6
80% chanceOct 9
90% chanceOct 13
Probability of light freeze (32°F) on or before...
10% chanceSep 28
20% chanceOct 2
30% chanceOct 6
40% chanceOct 9
50% chanceOct 13
60% chanceOct 16
70% chanceOct 19
80% chanceOct 22
90% chanceOct 27
Probability of moderate freeze (28°F) on or before...
10% chanceOct 10
20% chanceOct 17
30% chanceOct 21
40% chanceOct 25
50% chanceOct 28
60% chanceNov 1
70% chanceNov 3
80% chanceNov 7
90% chanceNov 15
Probability of moderate hard freeze (24°F) on or before...
10% chanceOct 24
20% chanceOct 31
30% chanceNov 3
40% chanceNov 6
50% chanceNov 10
60% chanceNov 14
70% chanceNov 19
80% chanceNov 24
90% chanceDec 1
Probability of hard freeze (20°F) on or before...
10% chanceNov 1
20% chanceNov 7
30% chanceNov 12
40% chanceNov 18
50% chanceNov 23
60% chanceNov 27
70% chanceDec 1
80% chanceDec 7
90% chanceDec 16
Probability of severe hard freeze (16°F) on or before...
10% chanceNov 8
20% chanceNov 17
30% chanceNov 24
40% chanceNov 30
50% chanceDec 5
60% chanceDec 10
70% chanceDec 17
80% chanceDec 24
90% chanceJan 2

Agricultural climatic data from weather station: BIGFORK 13 S (USC00240755)

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