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🍂 First Frost Dates for Hysham, Montana 59038

The first 36°F frost date is 30% likely to be on Sep 11. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Sep 20. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Hysham, 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 4
20% chanceSep 8
30% chanceSep 11
40% chanceSep 14
50% chanceSep 16
60% chanceSep 19
70% chanceSep 21
80% chanceSep 24
90% chanceSep 28
Probability of light freeze (32°F) on or before...
10% chanceSep 12
20% chanceSep 17
30% chanceSep 20
40% chanceSep 22
50% chanceSep 25
60% chanceSep 27
70% chanceSep 30
80% chanceOct 2
90% chanceOct 5
Probability of moderate freeze (28°F) on or before...
10% chanceSep 20
20% chanceSep 25
30% chanceSep 28
40% chanceOct 1
50% chanceOct 3
60% chanceOct 5
70% chanceOct 8
80% chanceOct 12
90% chanceOct 16
Probability of moderate hard freeze (24°F) on or before...
10% chanceSep 28
20% chanceOct 2
30% chanceOct 6
40% chanceOct 10
50% chanceOct 13
60% chanceOct 16
70% chanceOct 19
80% chanceOct 23
90% chanceOct 27
Probability of hard freeze (20°F) on or before...
10% chanceOct 6
20% chanceOct 13
30% chanceOct 17
40% chanceOct 20
50% chanceOct 23
60% chanceOct 27
70% chanceOct 30
80% chanceNov 2
90% chanceNov 8
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 17
20% chanceOct 22
30% chanceOct 27
40% chanceOct 30
50% chanceNov 2
60% chanceNov 5
70% chanceNov 9
80% chanceNov 14
90% chanceNov 20

Agricultural climatic data from weather station: HYSHAM (USC00244358)

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