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

In the Spring
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
Last 16° Apr 12 Apr 5 Mar 31 Mar 27 Mar 23 Mar 19 Mar 15 Mar 10 Mar 3
Last 20° Apr 21 Apr 14 Apr 9 Apr 5 Apr 1 Mar 28 Mar 24 Mar 19 Mar 13
Last 24° May 1 Apr 26 Apr 23 Apr 20 Apr 17 Apr 14 Apr 11 Apr 7 Apr 2
Last 28° May 8 May 3 Apr 30 Apr 27 Apr 24 Apr 22 Apr 19 Apr 15 Apr 10
Last 32° May 18 May 13 May 10 May 7 May 5 May 2 Apr 29 Apr 26 Apr 22
Last 36° May 31 May 26 May 22 May 19 May 17 May 14 May 11 May 7 May 2

In the Fall
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
First 16° Oct 26 Oct 30 Nov 3 Nov 5 Nov 8 Nov 10 Nov 13 Nov 16 Nov 21
First 20° Oct 9 Oct 15 Oct 19 Oct 23 Oct 27 Oct 30 Nov 3 Nov 7 Nov 14
First 24° Sep 28 Oct 4 Oct 8 Oct 12 Oct 16 Oct 19 Oct 23 Oct 27 Nov 2
First 28° Sep 22 Sep 28 Oct 2 Oct 5 Oct 8 Oct 11 Oct 15 Oct 19 Oct 24
First 32° Sep 15 Sep 19 Sep 23 Sep 25 Sep 28 Sep 30 Oct 3 Oct 6 Oct 10
First 36° Sep 10 Sep 14 Sep 17 Sep 19 Sep 21 Sep 23 Sep 25 Sep 28 Oct 2

Now that you know your frost dates, use our Garden Planting Calendar for Longmont, 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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