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

ℹ️ How to read these charts for the spring

As spring unfolds, the risk of frost gradually decreases each day until your tender plants are finally safe. The probabilities shown in the chart help you make smart decisions about when to plant.

While frost typically forms at 32°F, tender plants can be damaged even when temperatures are slightly higher. Air temperatures are often measured several feet above the ground, but temperatures at plant level can be several degrees colder. Protected areas like porches help by blocking radiational cooling. Given these variables, we consider 36°F the "caution zone" for frost-sensitive plants.

Key dates for your spring planting:

  • By July 3, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around June 13, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before May 31, there's still an 80% risk of frost — too early for tomatoes and other tender plants unless you're prepared to protect them

If the 10-day forecast shows no temperatures below 40°F, you might safely plant earlier than the above dates suggest. Many gardeners watch for this weather window to get a head start on the growing season.

In the Spring
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
Last 16° Apr 16 Apr 12 Apr 8 Apr 5 Apr 2 Mar 31 Mar 28 Mar 24 Mar 19
Last 20° May 2 Apr 27 Apr 23 Apr 20 Apr 17 Apr 15 Apr 12 Apr 8 Apr 3
Last 24° May 13 May 8 May 4 May 1 Apr 28 Apr 25 Apr 22 Apr 18 Apr 13
Last 28° May 29 May 24 May 20 May 17 May 15 May 12 May 9 May 5 Apr 30
Last 32° Jun 17 Jun 11 Jun 8 Jun 4 Jun 1 May 29 May 26 May 22 May 17
Last 36° Jul 3 Jun 26 Jun 21 Jun 17 Jun 13 Jun 9 Jun 5 May 31 May 24

ℹ️ How to read these charts for the fall

As summer ends in Stephenson, MI, nighttime temperatures begin to drop, and your risk of frost increases with each passing day. Knowing when to expect frost helps you harvest sensitive crops and extend your growing season with protection methods.

The chart below shows the probability of experiencing specific temperatures on various dates. Here's what this means for your garden:

1
Early warning: Around September 10, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By September 17, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By September 25, there's an 80% chance of seeing 32°F — most tender plants will be damaged without protection
4
Another perspective: You have only a 1 in 5 chance of making it past September 25 without a freezing night

These probabilities help you time your end-of-season harvests and know when to apply protective measures like row covers, cloches, or cold frames to extend your harvest.

In the Fall
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
First 16° Oct 24 Oct 30 Nov 4 Nov 7 Nov 11 Nov 14 Nov 18 Nov 22 Nov 28
First 20° Oct 13 Oct 19 Oct 23 Oct 26 Oct 30 Nov 2 Nov 6 Nov 10 Nov 15
First 24° Sep 27 Oct 2 Oct 5 Oct 9 Oct 11 Oct 14 Oct 17 Oct 21 Oct 26
First 28° Sep 18 Sep 22 Sep 25 Sep 27 Sep 30 Oct 2 Oct 5 Oct 8 Oct 12
First 32° Sep 6 Sep 10 Sep 13 Sep 15 Sep 17 Sep 20 Sep 22 Sep 25 Sep 29
First 36° Aug 19 Aug 25 Aug 30 Sep 2 Sep 6 Sep 9 Sep 13 Sep 17 Sep 23

📍 Frost Dates for other nearby locations

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