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🍂 First Frost Dates for Byron, Illinois 61010

The first 36°F frost date is 30% likely to be on Sep 27. (See detailed probabilities below.)

The first 32°F light freeze date is 30% likely to be on Oct 5. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Byron, IL 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 20
20% chanceSep 24
30% chanceSep 27
40% chanceSep 29
50% chanceOct 1
60% chanceOct 3
70% chanceOct 6
80% chanceOct 9
90% chanceOct 13
Probability of light freeze (32°F) on or before...
10% chanceSep 28
20% chanceOct 2
30% chanceOct 5
40% chanceOct 8
50% chanceOct 11
60% chanceOct 13
70% chanceOct 17
80% chanceOct 20
90% chanceOct 25
Probability of moderate freeze (28°F) on or before...
10% chanceOct 6
20% chanceOct 12
30% chanceOct 16
40% chanceOct 20
50% chanceOct 23
60% chanceOct 26
70% chanceOct 29
80% chanceNov 1
90% chanceNov 6
Probability of moderate hard freeze (24°F) on or before...
10% chanceOct 18
20% chanceOct 24
30% chanceOct 28
40% chanceNov 1
50% chanceNov 3
60% chanceNov 6
70% chanceNov 10
80% chanceNov 14
90% chanceNov 19
Probability of hard freeze (20°F) on or before...
10% chanceOct 31
20% chanceNov 4
30% chanceNov 8
40% chanceNov 12
50% chanceNov 15
60% chanceNov 19
70% chanceNov 22
80% chanceNov 25
90% chanceNov 30
Probability of severe hard freeze (16°F) on or before...
10% chanceNov 9
20% chanceNov 15
30% chanceNov 19
40% chanceNov 22
50% chanceNov 25
60% chanceNov 28
70% chanceDec 1
80% chanceDec 4
90% chanceDec 10

Agricultural climatic data from weather station: ROCKFORD GTR ROCKFORD AP (USW00094822)

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