Frost Dates: First and last frost dates for Lewes, DE

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 April 30. 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 9, so we don't dare plant that early. We wait a few days and by April 17 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 4 Feb 24 Feb 19 Feb 14 Feb 10 Feb 6 Feb 1 Jan 26 Jan 17
Last 20° Mar 21 Mar 13 Mar 7 Mar 2 Feb 25 Feb 21 Feb 15 Feb 9 Feb 1
Last 24° Mar 30 Mar 23 Mar 18 Mar 14 Mar 10 Mar 6 Mar 2 Feb 25 Feb 18
Last 28° Apr 10 Apr 3 Mar 29 Mar 26 Mar 22 Mar 18 Mar 14 Mar 9 Mar 3
Last 32° Apr 20 Apr 15 Apr 12 Apr 8 Apr 6 Apr 3 Mar 31 Mar 27 Mar 22
Last 36° Apr 30 Apr 26 Apr 23 Apr 20 Apr 17 Apr 15 Apr 12 Apr 9 Apr 4

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for Lewes, DE 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 21, and by November 14 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 26.
  2. There is a 50% chance of being hit by a 32° frost starting around November 5
  3. You have a 80% chance of seeing 32° by November 14
  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 13 Dec 20 Dec 26 Dec 30 Jan 3 Jan 7 Jan 12 Jan 17 Jan 26
First 20° Dec 2 Dec 8 Dec 12 Dec 16 Dec 19 Dec 22 Dec 26 Dec 30 Jan 5
First 24° Nov 22 Nov 27 Dec 2 Dec 5 Dec 8 Dec 12 Dec 15 Dec 19 Dec 25
First 28° Oct 29 Nov 5 Nov 10 Nov 14 Nov 18 Nov 22 Nov 27 Dec 2 Dec 9
First 32° Oct 21 Oct 26 Oct 29 Nov 2 Nov 5 Nov 7 Nov 11 Nov 14 Nov 19
First 36° Oct 10 Oct 15 Oct 19 Oct 23 Oct 26 Oct 29 Nov 2 Nov 6 Nov 11

Frost Dates for other nearby locations
  • Milford, DE
  • Cape May, NJ
  • Salisbury, MD
  • Snow Hill, MD
  • Salisbury, MD
  • Belleplain Stn Forest, NJ
  • Dover, DE
  • Milville, NJ
  • Assateague, MD
  • Vienna, MD

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