Frost Dates: First and last frost dates for Boulder, CO

In the Spring
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
Last 16° Apr 13 Apr 5 Mar 30 Mar 25 Mar 21 Mar 16 Mar 11 Mar 5 Feb 25
Last 20° Apr 19 Apr 13 Apr 8 Apr 5 Apr 1 Mar 29 Mar 25 Mar 21 Mar 14
Last 24° Apr 26 Apr 21 Apr 17 Apr 13 Apr 10 Apr 7 Apr 3 Mar 30 Mar 25
Last 28° May 7 May 2 Apr 28 Apr 25 Apr 22 Apr 20 Apr 17 Apr 13 Apr 8
Last 32° May 14 May 10 May 8 May 6 May 4 May 2 Apr 30 Apr 27 Apr 24
Last 36° May 31 May 26 May 22 May 19 May 16 May 14 May 10 May 7 May 2

In the Fall
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
First 16° Oct 20 Oct 29 Nov 4 Nov 9 Nov 14 Nov 19 Nov 24 Nov 30 Dec 8
First 20° Oct 15 Oct 22 Oct 26 Oct 30 Nov 3 Nov 6 Nov 10 Nov 15 Nov 21
First 24° Oct 3 Oct 10 Oct 15 Oct 20 Oct 24 Oct 28 Nov 2 Nov 7 Nov 14
First 28° Sep 23 Sep 29 Oct 4 Oct 8 Oct 11 Oct 15 Oct 19 Oct 23 Oct 30
First 32° Sep 18 Sep 23 Sep 26 Sep 29 Oct 2 Oct 5 Oct 8 Oct 11 Oct 16
First 36° Sep 14 Sep 18 Sep 21 Sep 23 Sep 26 Sep 28 Oct 1 Oct 4 Oct 8

Now that you know your frost dates, use our Garden Planting Calendar for Boulder, CO to know when to sow and transplant your various vegetable plants!

Data is provided by the NOAA National Centers for Environmental Information. Photography by Garden.org member TBGDN.

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