Frost Dates: First and last frost dates for manistique wwtp, mi

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for manistique wwtp, mi 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 September 4, and by October 12 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 September 12.
  2. There is a 50% chance of being hit by a 32° frost starting around September 27
  3. You have a 80% chance of seeing 32° by October 12
  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° Nov 5 Nov 11 Nov 15 Nov 18 Nov 21 Nov 24 Nov 28 Dec 2 Dec 7
First 20° Oct 22 Oct 29 Nov 2 Nov 6 Nov 10 Nov 14 Nov 18 Nov 22 Nov 29
First 24° Oct 13 Oct 20 Oct 25 Oct 29 Nov 2 Nov 5 Nov 10 Nov 14 Nov 21
First 28° Sep 25 Oct 2 Oct 7 Oct 11 Oct 15 Oct 18 Oct 23 Oct 27 Nov 3
First 32° Sep 4 Sep 12 Sep 18 Sep 23 Sep 27 Oct 2 Oct 7 Oct 12 Oct 20
First 36° Aug 29 Sep 5 Sep 10 Sep 14 Sep 18 Sep 22 Sep 26 Oct 1 Oct 8

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 June 17. 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 May 18, so we don't dare plant that early. We wait a few days and by May 30 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° Apr 14 Apr 10 Apr 7 Apr 4 Apr 2 Mar 30 Mar 28 Mar 25 Mar 20
Last 20° Apr 24 Apr 19 Apr 15 Apr 12 Apr 9 Apr 6 Apr 2 Mar 30 Mar 24
Last 24° May 4 Apr 29 Apr 26 Apr 22 Apr 19 Apr 17 Apr 13 Apr 10 Apr 5
Last 28° May 23 May 17 May 12 May 8 May 4 Apr 30 Apr 26 Apr 21 Apr 15
Last 32° Jun 4 May 29 May 24 May 20 May 17 May 13 May 10 May 5 Apr 29
Last 36° Jun 17 Jun 11 Jun 6 Jun 2 May 30 May 26 May 23 May 18 May 12

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