Frost Dates: First and last frost dates for Frederick Police Brks, 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 11, so we don't dare plant that early. We wait a few days and by April 22 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 17 Mar 8 Mar 1 Feb 23 Feb 17 Feb 11 Feb 5 Jan 29 Jan 17
Last 20° Mar 30 Mar 21 Mar 15 Mar 9 Mar 4 Feb 27 Feb 21 Feb 15 Feb 4
Last 24° Apr 1 Mar 27 Mar 23 Mar 20 Mar 16 Mar 13 Mar 10 Mar 6 Mar 1
Last 28° Apr 15 Apr 9 Apr 4 Mar 31 Mar 28 Mar 24 Mar 20 Mar 15 Mar 9
Last 32° Apr 19 Apr 16 Apr 13 Apr 11 Apr 9 Apr 7 Apr 4 Apr 2 Mar 29
Last 36° May 8 May 2 Apr 28 Apr 25 Apr 22 Apr 19 Apr 15 Apr 11 Apr 6

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for Frederick Police Brks, 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 13, and by November 9 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 19.
  2. There is a 50% chance of being hit by a 32° frost starting around October 30
  3. You have a 80% chance of seeing 32° by November 9
  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 11 Dec 15 Dec 18 Dec 22 Dec 25 Dec 28 Jan 1 Jan 6
First 20° Nov 26 Dec 1 Dec 5 Dec 9 Dec 12 Dec 15 Dec 19 Dec 23 Dec 29
First 24° Nov 11 Nov 17 Nov 22 Nov 26 Nov 29 Dec 3 Dec 7 Dec 11 Dec 18
First 28° Oct 29 Nov 3 Nov 8 Nov 11 Nov 15 Nov 18 Nov 21 Nov 26 Dec 1
First 32° Oct 13 Oct 19 Oct 23 Oct 26 Oct 30 Nov 2 Nov 5 Nov 9 Nov 15
First 36° Oct 1 Oct 7 Oct 10 Oct 14 Oct 17 Oct 20 Oct 23 Oct 27 Nov 1

Frost Dates for other nearby locations
  • Catoctin Mtn Park, MD
  • Emmitsburg, MD
  • Rockville, MD
  • Lincoln, VA
  • Clarksville, MD
  • Washgtn Dulles, VA
  • Vienna, VA
  • Dalecarlia Rsvr, MD
  • Laurel, MD
  • Beltsville, MD

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