Frost Dates: First and last frost dates for Dalecarlia Rsvr, MD

How to read these charts for the spring
As the growing season approaches, the days get longer, the weather begins to warm up, and the nights start being less cold. You're still getting frost, but the chance of nightly frosts gets less and less with each passing day. Eventually, the frost stops, and this is when your tender plants are fully safe. So, how do you plan for this? The probabilities on this page help you assess your risk of frost on any given day.

What's a safe temperature for tender plants? When the nightly temperature falls, frost can form, even above 32°, because the air is colder high above the ground and the frost can form up there and then fall down onto your garden and do some damage, even if it's 36° on the ground. So many factors come into play, including wind, concrete, houses, trees and other structures, etc etc etc. Because of all this, you might want to consider 36° as "the danger zone".

In your average springtime, you have a 90% chance that there will be no 36° nights by May 8. In other words, you can pretty much count on being safe from frost by that day. But we want to get those tomatoes in the ground as soon as possible, right? We see that there's still an 80% chance of 36° on April 14, so we don't dare plant that early. We wait a few days and by April 24 we are at the 50/50 point. At this point, we are close and we can start watching the weather forecast. If the upcoming week's forecast doesn't show below 40°, then it's probably okay to risk planting out your plants.

In the Spring
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
Last 16° Mar 6 Feb 28 Feb 24 Feb 20 Feb 17 Feb 13 Feb 10 Feb 5 Jan 29
Last 20° Mar 18 Mar 13 Mar 9 Mar 6 Mar 2 Feb 27 Feb 24 Feb 20 Feb 15
Last 24° Mar 29 Mar 24 Mar 20 Mar 17 Mar 14 Mar 12 Mar 9 Mar 5 Feb 28
Last 28° Apr 12 Apr 8 Apr 4 Apr 2 Mar 30 Mar 28 Mar 25 Mar 22 Mar 17
Last 32° Apr 22 Apr 18 Apr 16 Apr 13 Apr 11 Apr 9 Apr 7 Apr 4 Mar 31
Last 36° May 8 May 4 Apr 30 Apr 27 Apr 24 Apr 21 Apr 18 Apr 14 Apr 10

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for Dalecarlia Rsvr, MD start to go down, and therefore every day that goes by increases the chance that you'll get frost. Your risk of frost really begins around October 17, and by November 7 you're almost certain to have received at least one frost event.

The charts on this page show the probabilities of receiving a certain temperature on a certain day. Some examples that might help:

  1. You have a small 20% chance of getting 32° by October 21.
  2. There is a 50% chance of being hit by a 32° frost starting around October 29
  3. You have a 80% chance of seeing 32° by November 7
  4. Said another way, you have a 1 in 5 chance at making it to that day without a 32° night.
In the Fall
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
First 16° Dec 6 Dec 12 Dec 17 Dec 22 Dec 26 Dec 30 Jan 3 Jan 9 Jan 17
First 20° Nov 21 Nov 27 Dec 1 Dec 5 Dec 9 Dec 12 Dec 16 Dec 21 Dec 27
First 24° Nov 10 Nov 15 Nov 18 Nov 21 Nov 24 Nov 27 Nov 30 Dec 3 Dec 8
First 28° Oct 24 Oct 30 Nov 3 Nov 6 Nov 10 Nov 13 Nov 16 Nov 20 Nov 26
First 32° Oct 17 Oct 21 Oct 24 Oct 27 Oct 29 Nov 1 Nov 4 Nov 7 Nov 11
First 36° Oct 4 Oct 8 Oct 12 Oct 14 Oct 17 Oct 20 Oct 22 Oct 26 Oct 30

Frost Dates for other nearby locations
  • Annapolis Police Brks, MD
  • Glenn Dale Bell Stn, MD
  • Upper Marlboro, MD
  • Laurel, MD
  • Beltsville, MD
  • Natl Arboretum Dc, MD
  • Clarksville, MD
  • Washington Reagan, VA
  • Dalecarlia Rsvr, MD
  • Rockville, MD

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    • Data is provided by the NOAA National Centers for Environmental Information.