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🍂 First Frost Dates for Capitol, Montana 59319

The first 36°F frost date is 30% likely to be on Sep 3. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Sep 12. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Capitol, 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% chanceAug 26
20% chanceSep 1
30% chanceSep 3
40% chanceSep 6
50% chanceSep 9
60% chanceSep 11
70% chanceSep 14
80% chanceSep 17
90% chanceSep 22
Probability of light freeze (32°F) on or before...
10% chanceSep 4
20% chanceSep 8
30% chanceSep 12
40% chanceSep 15
50% chanceSep 18
60% chanceSep 20
70% chanceSep 23
80% chanceSep 26
90% chanceOct 1
Probability of moderate freeze (28°F) on or before...
10% chanceSep 11
20% chanceSep 16
30% chanceSep 20
40% chanceSep 23
50% chanceSep 26
60% chanceSep 29
70% chanceOct 1
80% chanceOct 5
90% chanceOct 9
Probability of moderate hard freeze (24°F) on or before...
10% chanceSep 18
20% chanceSep 24
30% chanceSep 28
40% chanceOct 1
50% chanceOct 4
60% chanceOct 7
70% chanceOct 11
80% chanceOct 15
90% chanceOct 20
Probability of hard freeze (20°F) on or before...
10% chanceSep 26
20% chanceOct 3
30% chanceOct 7
40% chanceOct 11
50% chanceOct 15
60% chanceOct 18
70% chanceOct 21
80% chanceOct 25
90% chanceOct 30
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 5
20% chanceOct 12
30% chanceOct 17
40% chanceOct 20
50% chanceOct 23
60% chanceOct 27
70% chanceOct 30
80% chanceNov 3
90% chanceNov 9

Agricultural climatic data from weather station: CAMP CROOK (USC00391294)

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