Frost Dates: First and last frost dates for Bellefontaine, OH

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 May 20, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around May 7, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before April 29, 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 1 Mar 26 Mar 22 Mar 19 Mar 15 Mar 12 Mar 8 Mar 4 Feb 26
Last 20° Apr 13 Apr 7 Apr 3 Mar 30 Mar 27 Mar 23 Mar 20 Mar 15 Mar 10
Last 24° Apr 18 Apr 14 Apr 11 Apr 8 Apr 6 Apr 3 Apr 1 Mar 29 Mar 24
Last 28° Apr 28 Apr 23 Apr 20 Apr 17 Apr 14 Apr 11 Apr 8 Apr 5 Mar 31
Last 32° May 15 May 9 May 5 May 2 Apr 29 Apr 25 Apr 22 Apr 18 Apr 12
Last 36° May 20 May 16 May 12 May 10 May 7 May 5 May 2 Apr 29 Apr 24

ℹ️ How to read these charts for the fall

As summer ends in Bellefontaine, OH, 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 October 2, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By October 11, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By October 20, 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 October 20 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° Nov 11 Nov 17 Nov 22 Nov 26 Nov 30 Dec 3 Dec 7 Dec 12 Dec 18
First 20° Nov 2 Nov 8 Nov 12 Nov 16 Nov 20 Nov 23 Nov 27 Dec 2 Dec 8
First 24° Oct 20 Oct 25 Oct 29 Nov 2 Nov 5 Nov 8 Nov 12 Nov 16 Nov 21
First 28° Oct 8 Oct 14 Oct 18 Oct 22 Oct 25 Oct 29 Nov 1 Nov 6 Nov 12
First 32° Sep 27 Oct 2 Oct 5 Oct 8 Oct 11 Oct 14 Oct 17 Oct 20 Oct 25
First 36° Sep 21 Sep 24 Sep 27 Sep 29 Oct 1 Oct 4 Oct 6 Oct 9 Oct 12

📍 Frost Dates for other nearby locations

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