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🍂 First Frost Dates for Fortine, Montana 59918

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 4. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Fortine, 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% chanceAug 27
20% chanceSep 1
30% chanceSep 4
40% chanceSep 7
50% chanceSep 10
60% chanceSep 13
70% chanceSep 17
80% chanceSep 21
90% chanceSep 27
Probability of moderate freeze (28°F) on or before...
10% chanceSep 8
20% chanceSep 13
30% chanceSep 17
40% chanceSep 21
50% chanceSep 24
60% chanceSep 27
70% chanceOct 1
80% chanceOct 3
90% chanceOct 8
Probability of moderate hard freeze (24°F) on or before...
10% chanceSep 19
20% chanceSep 26
30% chanceSep 29
40% chanceOct 1
50% chanceOct 4
60% chanceOct 7
70% chanceOct 12
80% chanceOct 17
90% chanceOct 23
Probability of hard freeze (20°F) on or before...
10% chanceOct 1
20% chanceOct 4
30% chanceOct 9
40% chanceOct 14
50% chanceOct 19
60% chanceOct 23
70% chanceOct 28
80% chanceNov 1
90% chanceNov 8
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 9
20% chanceOct 19
30% chanceOct 25
40% chanceOct 30
50% chanceNov 1
60% chanceNov 6
70% chanceNov 11
80% chanceNov 17
90% chanceNov 26

Agricultural climatic data from weather station: FORTINE 1 N (USC00243139)

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