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🍂 First Frost Dates for Harleigh, Pennsylvania 18225

The first 36°F frost date is 30% likely to be on Sep 12. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Sep 24. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Harleigh, PA 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 2
20% chanceSep 7
30% chanceSep 12
40% chanceSep 16
50% chanceSep 18
60% chanceSep 21
70% chanceSep 24
80% chanceSep 28
90% chanceOct 1
Probability of light freeze (32°F) on or before...
10% chanceSep 15
20% chanceSep 21
30% chanceSep 24
40% chanceSep 28
50% chanceSep 30
60% chanceOct 2
70% chanceOct 4
80% chanceOct 8
90% chanceOct 14
Probability of moderate freeze (28°F) on or before...
10% chanceSep 28
20% chanceOct 1
30% chanceOct 4
40% chanceOct 6
50% chanceOct 9
60% chanceOct 13
70% chanceOct 17
80% chanceOct 23
90% chanceNov 1
Probability of moderate hard freeze (24°F) on or before...
10% chanceOct 6
20% chanceOct 11
30% chanceOct 16
40% chanceOct 20
50% chanceOct 24
60% chanceOct 29
70% chanceNov 2
80% chanceNov 6
90% chanceNov 14
Probability of hard freeze (20°F) on or before...
10% chanceOct 18
20% chanceOct 25
30% chanceOct 31
40% chanceNov 3
50% chanceNov 7
60% chanceNov 12
70% chanceNov 17
80% chanceNov 22
90% chanceNov 30
Probability of severe hard freeze (16°F) on or before...
10% chanceNov 3
20% chanceNov 10
30% chanceNov 15
40% chanceNov 19
50% chanceNov 23
60% chanceNov 27
70% chanceDec 1
80% chanceDec 5
90% chanceDec 11

Agricultural climatic data from weather station: FRANCIS E WALTER DAM (USC00363018)

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