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🍂 First Frost Dates for Napa, California 94559

The first 36°F frost date is 30% likely to be on Nov 10. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Nov 29. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Napa, CA 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% chanceNov 1
20% chanceNov 6
30% chanceNov 10
40% chanceNov 15
50% chanceNov 19
60% chanceNov 23
70% chanceNov 27
80% chanceDec 1
90% chanceDec 6
Probability of light freeze (32°F) on or before...
10% chanceNov 17
20% chanceNov 24
30% chanceNov 29
40% chanceDec 2
50% chanceDec 5
60% chanceDec 10
70% chanceDec 17
80% chanceDec 26
90% chanceJan 6
Probability of moderate freeze (28°F) on or before...
10% chanceDec 2
20% chanceDec 8
30% chanceDec 13
40% chanceDec 19
50% chanceDec 25
60% chanceJan 1
70% chanceJan 4
80% chanceJan 11
90% chanceJan 24
Probability of moderate hard freeze (24°F) on or before...
10% chanceDec 6
20% chanceDec 12
30% chanceDec 18
40% chanceDec 24
50% chanceDec 30
60% chanceJan 2
70% chanceJan 6
80% chanceJan 12
90% chanceJan 24
Probability of hard freeze (20°F) on or before...
10% chancerarely
20% chancerarely
30% chancerarely
40% chancerarely
50% chancerarely
60% chancerarely
70% chancerarely
80% chancerarely
90% chancerarely
Probability of severe hard freeze (16°F) on or before...
10% chancerarely
20% chancerarely
30% chancerarely
40% chancerarely
50% chancerarely
60% chancerarely
70% chancerarely
80% chancerarely
90% chancerarely

Agricultural climatic data from weather station: NAPA STATE HOSPITAL (USC00046074)

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