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🍂 First Frost Dates for Mountain Home, Idaho 83647

The first 36°F frost date is 30% likely to be on Sep 17. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Sep 28. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Mountain Home, ID 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 9
20% chanceSep 13
30% chanceSep 17
40% chanceSep 20
50% chanceSep 23
60% chanceSep 26
70% chanceSep 29
80% chanceOct 2
90% chanceOct 6
Probability of light freeze (32°F) on or before...
10% chanceSep 20
20% chanceSep 25
30% chanceSep 28
40% chanceOct 1
50% chanceOct 3
60% chanceOct 6
70% chanceOct 9
80% chanceOct 13
90% chanceOct 18
Probability of moderate freeze (28°F) on or before...
10% chanceSep 30
20% chanceOct 5
30% chanceOct 9
40% chanceOct 13
50% chanceOct 16
60% chanceOct 18
70% chanceOct 22
80% chanceOct 25
90% chanceNov 1
Probability of moderate hard freeze (24°F) on or before...
10% chanceOct 13
20% chanceOct 18
30% chanceOct 22
40% chanceOct 25
50% chanceOct 28
60% chanceNov 1
70% chanceNov 4
80% chanceNov 9
90% chanceNov 16
Probability of hard freeze (20°F) on or before...
10% chanceOct 24
20% chanceOct 29
30% chanceNov 1
40% chanceNov 5
50% chanceNov 10
60% chanceNov 15
70% chanceNov 20
80% chanceNov 25
90% chanceDec 1
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 31
20% chanceNov 6
30% chanceNov 13
40% chanceNov 19
50% chanceNov 25
60% chanceNov 29
70% chanceDec 3
80% chanceDec 8
90% chanceDec 16

Agricultural climatic data from weather station: MTN HOME (USC00106174)

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