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🍂 First Frost Dates for Fort Defiance, Arizona 86504

The first 36°F frost date is 30% likely to be on Sep 18. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Sep 25. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Fort Defiance, AZ 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 10
20% chanceSep 15
30% chanceSep 18
40% chanceSep 21
50% chanceSep 23
60% chanceSep 25
70% chanceSep 28
80% chanceOct 1
90% chanceOct 4
Probability of light freeze (32°F) on or before...
10% chanceSep 17
20% chanceSep 22
30% chanceSep 25
40% chanceSep 28
50% chanceOct 1
60% chanceOct 3
70% chanceOct 6
80% chanceOct 10
90% chanceOct 14
Probability of moderate freeze (28°F) on or before...
10% chanceSep 25
20% chanceOct 1
30% chanceOct 4
40% chanceOct 8
50% chanceOct 11
60% chanceOct 14
70% chanceOct 17
80% chanceOct 21
90% chanceOct 25
Probability of moderate hard freeze (24°F) on or before...
10% chanceOct 7
20% chanceOct 13
30% chanceOct 17
40% chanceOct 20
50% chanceOct 23
60% chanceOct 26
70% chanceOct 29
80% chanceNov 1
90% chanceNov 5
Probability of hard freeze (20°F) on or before...
10% chanceOct 19
20% chanceOct 25
30% chanceOct 28
40% chanceOct 31
50% chanceNov 3
60% chanceNov 5
70% chanceNov 8
80% chanceNov 11
90% chanceNov 16
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 30
20% chanceNov 3
30% chanceNov 6
40% chanceNov 9
50% chanceNov 12
60% chanceNov 15
70% chanceNov 18
80% chanceNov 20
90% chanceNov 24

Agricultural climatic data from weather station: WINDOW ROCK 4 SW (USC00029410)

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