Frost Dates: First and last frost dates for Herman, MI

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 July 28. 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 June 11, so we don't dare plant that early. We wait a few days and by June 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° May 4 Apr 28 Apr 24 Apr 21 Apr 18 Apr 15 Apr 11 Apr 7 Apr 2
Last 20° May 15 May 9 May 5 May 1 Apr 28 Apr 24 Apr 20 Apr 16 Apr 10
Last 24° Jun 1 May 25 May 20 May 16 May 12 May 7 May 3 Apr 28 Apr 21
Last 28° Jun 19 Jun 12 Jun 7 Jun 2 May 29 May 25 May 21 May 15 May 8
Last 32° Jul 11 Jul 1 Jun 24 Jun 18 Jun 13 Jun 8 Jun 2 May 26 May 16
Last 36° Jul 28 Jul 18 Jul 11 Jul 5 Jun 30 Jun 24 Jun 18 Jun 11 Jun 2

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for Herman, 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 August 11, and by September 24 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 August 20.
  2. There is a 50% chance of being hit by a 32° frost starting around September 6
  3. You have a 80% chance of seeing 32° by September 24
  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° Oct 15 Oct 23 Oct 28 Nov 1 Nov 6 Nov 10 Nov 14 Nov 19 Nov 27
First 20° Oct 5 Oct 11 Oct 16 Oct 19 Oct 23 Oct 26 Oct 30 Nov 3 Nov 9
First 24° Sep 18 Sep 25 Sep 30 Oct 5 Oct 9 Oct 13 Oct 18 Oct 23 Oct 31
First 28° Sep 1 Sep 7 Sep 12 Sep 16 Sep 20 Sep 24 Sep 28 Oct 3 Oct 10
First 32° Aug 11 Aug 20 Aug 27 Sep 1 Sep 6 Sep 12 Sep 17 Sep 24 Oct 3
First 36° Aug 4 Aug 12 Aug 17 Aug 22 Aug 26 Aug 30 Sep 4 Sep 9 Sep 16

Frost Dates for other nearby locations
  • Champion Van Riper Pk, MI
  • Houghton, MI
  • Kenton, MI
  • Stambaugh, MI
  • Marquette Wfo, MI
  • Iron Mt Kingsford Wwtp, MI
  • Marquette, MI
  • Goodman Sanitary Dist, WI
  • Eagle River, WI
  • Bergland Dam, MI

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