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🍂 First Frost Dates for Mills, Wyoming 82644

The first 36°F frost date is 30% likely to be on Sep 6. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Sep 16. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Mills, WY 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 30
20% chanceSep 3
30% chanceSep 6
40% chanceSep 9
50% chanceSep 11
60% chanceSep 14
70% chanceSep 16
80% chanceSep 19
90% chanceSep 23
Probability of light freeze (32°F) on or before...
10% chanceSep 9
20% chanceSep 13
30% chanceSep 16
40% chanceSep 18
50% chanceSep 21
60% chanceSep 23
70% chanceSep 26
80% chanceSep 29
90% chanceOct 2
Probability of moderate freeze (28°F) on or before...
10% chanceSep 17
20% chanceSep 21
30% chanceSep 25
40% chanceSep 27
50% chanceSep 30
60% chanceOct 2
70% chanceOct 4
80% chanceOct 7
90% chanceOct 11
Probability of moderate hard freeze (24°F) on or before...
10% chanceSep 26
20% chanceSep 30
30% chanceOct 3
40% chanceOct 6
50% chanceOct 9
60% chanceOct 12
70% chanceOct 14
80% chanceOct 18
90% chanceOct 22
Probability of hard freeze (20°F) on or before...
10% chanceOct 3
20% chanceOct 9
30% chanceOct 14
40% chanceOct 17
50% chanceOct 20
60% chanceOct 23
70% chanceOct 25
80% chanceOct 28
90% chanceNov 2
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 13
20% chanceOct 19
30% chanceOct 22
40% chanceOct 26
50% chanceOct 29
60% chanceNov 1
70% chanceNov 3
80% chanceNov 8
90% chanceNov 13

Agricultural climatic data from weather station: CASPER NATRONA CO AP (USW00024089)

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