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🍂 First Frost Dates for McAllister, Montana 59740

The first 36°F frost date is 30% likely to be on Sep 25. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Oct 4. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for McAllister, 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 15
20% chanceSep 21
30% chanceSep 25
40% chanceSep 28
50% chanceOct 1
60% chanceOct 3
70% chanceOct 6
80% chanceOct 10
90% chanceOct 15
Probability of light freeze (32°F) on or before...
10% chanceSep 26
20% chanceOct 1
30% chanceOct 4
40% chanceOct 8
50% chanceOct 12
60% chanceOct 15
70% chanceOct 19
80% chanceOct 22
90% chanceOct 26
Probability of moderate freeze (28°F) on or before...
10% chanceOct 3
20% chanceOct 11
30% chanceOct 17
40% chanceOct 20
50% chanceOct 24
60% chanceOct 27
70% chanceOct 31
80% chanceNov 4
90% chanceNov 10
Probability of moderate hard freeze (24°F) on or before...
10% chanceOct 17
20% chanceOct 23
30% chanceOct 27
40% chanceOct 31
50% chanceNov 3
60% chanceNov 7
70% chanceNov 11
80% chanceNov 16
90% chanceNov 22
Probability of hard freeze (20°F) on or before...
10% chanceOct 24
20% chanceOct 31
30% chanceNov 4
40% chanceNov 9
50% chanceNov 12
60% chanceNov 16
70% chanceNov 21
80% chanceNov 25
90% chanceNov 30
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 30
20% chanceNov 7
30% chanceNov 12
40% chanceNov 17
50% chanceNov 22
60% chanceNov 26
70% chanceNov 30
80% chanceDec 4
90% chanceDec 12

Agricultural climatic data from weather station: NORRIS MADISON PH (USC00246157)

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