Frost Dates: First and last frost dates for Marcus Hook, PA

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 20. 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 4, so we don't dare plant that early. We wait a few days and by April 10 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 7 Feb 28 Feb 23 Feb 18 Feb 14 Feb 9 Feb 4 Jan 29 Jan 17
Last 20° Mar 22 Mar 13 Mar 6 Mar 1 Feb 24 Feb 18 Feb 13 Feb 6 Jan 29
Last 24° Mar 26 Mar 20 Mar 15 Mar 11 Mar 8 Mar 4 Feb 28 Feb 24 Feb 17
Last 28° Apr 1 Mar 27 Mar 23 Mar 20 Mar 18 Mar 15 Mar 12 Mar 8 Mar 3
Last 32° Apr 14 Apr 8 Apr 5 Apr 2 Mar 30 Mar 27 Mar 24 Mar 20 Mar 15
Last 36° Apr 20 Apr 17 Apr 14 Apr 12 Apr 10 Apr 8 Apr 6 Apr 4 Mar 31

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for Marcus Hook, PA 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 28, and by November 26 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 November 3.
  2. There is a 50% chance of being hit by a 32° frost starting around November 14
  3. You have a 80% chance of seeing 32° by November 26
  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 15 Dec 23 Dec 28 Jan 2 Jan 7 Jan 11 Jan 17 Jan 24 Feb 5
First 20° Dec 4 Dec 12 Dec 17 Dec 22 Dec 26 Dec 31 Jan 5 Jan 10 Jan 18
First 24° Nov 27 Dec 3 Dec 7 Dec 11 Dec 14 Dec 18 Dec 21 Dec 25 Dec 31
First 28° Nov 15 Nov 20 Nov 23 Nov 26 Nov 29 Dec 2 Dec 5 Dec 9 Dec 14
First 32° Oct 28 Nov 3 Nov 7 Nov 11 Nov 14 Nov 18 Nov 21 Nov 26 Dec 2
First 36° Oct 20 Oct 26 Oct 29 Nov 2 Nov 5 Nov 8 Nov 11 Nov 15 Nov 21

Frost Dates for other nearby locations
  • Philadelphia, PA
  • Wilmington New Castle Co Ap, DE
  • West Chester, PA
  • Norristown, PA
  • Phoenixville, PA
  • Glassboro, NJ
  • Newark Univ Farm, DE
  • Woodstown Pittsgrov, NJ
  • Seabrook Farms, NJ
  • Graterford, PA

    Or enter a new zipcode:

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