First and last freeze/frost dates for Naperville, IL ,United States

First and last freeze/frost dates for:
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Each winter, on average, your risk of frost is from October 8 through May 6.

Almost certainly, however, you will receive frost from October 20 through April 17.

You are almost guaranteed that you will not get frost from May 24 through September 26.

Your frost-free growing season is around 155 days.

Detailed station data* follows:

Wheaton College, IL (Dupage county):

Temperature10%20%30%40%50%60%70%80%90%
Spring 32° May 24 May 18 May 13 May 10 May 6 May 2 Apr 28 Apr 24 Apr 17
Spring 28° May 8 May 2 Apr 28 Apr 25 Apr 22 Apr 19 Apr 16 Apr 12 Apr 6
Spring 24° Apr 20 Apr 17 Apr 15 Apr 13 Apr 11 Apr 9 Apr 8 Apr 5 Apr 2
Fall 32° Sep 26 Sep 30 Oct 3 Oct 6 Oct 8 Oct 10 Oct 13 Oct 16 Oct 20
Fall 28° Oct 4 Oct 9 Oct 14 Oct 17 Oct 20 Oct 24 Oct 27 Oct 31 Nov 5
Fall 24° Oct 22 Oct 26 Oct 29 Oct 31 Nov 2 Nov 5 Nov 8 Nov 11 Nov 15

Aurora College, IL (Kane county):

Temperature10%20%30%40%50%60%70%80%90%
Spring 32° May 16 May 10 May 6 May 3 Apr 29 Apr 26 Apr 23 Apr 19 Apr 13
Spring 28° Apr 24 Apr 21 Apr 18 Apr 16 Apr 14 Apr 11 Apr 9 Apr 6 Apr 3
Spring 24° Apr 18 Apr 14 Apr 11 Apr 8 Apr 5 Apr 3 Mar 31 Mar 28 Mar 24
Fall 32° Sep 28 Oct 2 Oct 5 Oct 7 Oct 9 Oct 11 Oct 14 Oct 16 Oct 20
Fall 28° Oct 3 Oct 9 Oct 13 Oct 17 Oct 21 Oct 24 Oct 28 Oct 31 Nov 7
Fall 24° Oct 17 Oct 22 Oct 26 Oct 29 Oct 31 Nov 4 Nov 7 Nov 11 Nov 16

De Kalb, IL (Dekalb county):

Temperature10%20%30%40%50%60%70%80%90%
Spring 32° May 15 May 9 May 5 May 2 Apr 28 Apr 25 Apr 21 Apr 17 Apr 11
Spring 28° May 1 Apr 26 Apr 22 Apr 19 Apr 16 Apr 13 Apr 10 Apr 7 Apr 2
Spring 24° Apr 21 Apr 16 Apr 13 Apr 10 Apr 7 Apr 4 Apr 1 Mar 28 Mar 24
Fall 32° Sep 25 Sep 29 Oct 3 Oct 6 Oct 8 Oct 11 Oct 14 Oct 17 Oct 22
Fall 28° Oct 2 Oct 9 Oct 14 Oct 18 Oct 21 Oct 25 Oct 29 Nov 2 Nov 9
Fall 24° Oct 18 Oct 24 Oct 27 Oct 31 Nov 2 Nov 5 Nov 8 Nov 11 Nov 17

* This station data is available courtesy the National Climatic Data Center.

For each weather station, you will see a temperature along with tables of data organized into percentage columns. The percentage column tells you the probability that you will experience that row's temperature on or near that date. Here are two examples to help you determine your probable last frost and first freeze dates.

Example 1 (Last Frost). In the Spring 32° row, if you have "Apr 15" under the 50% column, that means you have a 50% chance of seeing frost on or before April 15th.

Example 2 (First Freeze). In the Fall 24° row, if you have "Dec 1" under the 90% column, that means you have a 90% chance of seeing 24 degrees on or after December 1st.

Empty cells indicate you have a less than 10% chance of ever seeing that temperature.

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