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🍂 First Frost Dates for Rock Springs, Wyoming 82901

The first 36°F frost date is 30% likely to be on Sep 7. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Sep 17. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Rock Springs, 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 31
20% chanceSep 4
30% chanceSep 7
40% chanceSep 10
50% chanceSep 13
60% chanceSep 15
70% chanceSep 17
80% chanceSep 21
90% chanceSep 25
Probability of light freeze (32°F) on or before...
10% chanceSep 9
20% chanceSep 14
30% chanceSep 17
40% chanceSep 20
50% chanceSep 23
60% chanceSep 25
70% chanceSep 28
80% chanceOct 1
90% chanceOct 4
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 30
20% chanceOct 5
30% chanceOct 9
40% chanceOct 12
50% chanceOct 16
60% chanceOct 19
70% chanceOct 21
80% chanceOct 24
90% chanceOct 28
Probability of hard freeze (20°F) on or before...
10% chanceOct 11
20% chanceOct 18
30% chanceOct 22
40% chanceOct 25
50% chanceOct 28
60% chanceOct 31
70% chanceNov 2
80% chanceNov 6
90% chanceNov 11
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 25
20% chanceOct 31
30% chanceNov 3
40% chanceNov 6
50% chanceNov 10
60% chanceNov 13
70% chanceNov 16
80% chanceNov 20
90% chanceNov 25

Agricultural climatic data from weather station: ALLEN'S RCH (USC00420050)

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