Frost Dates: First and last frost dates for Mt Vernon, IN

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 April 28, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around April 15, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before April 6, 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° Mar 12 Mar 4 Feb 26 Feb 21 Feb 16 Feb 12 Feb 6 Feb 1 Jan 23
Last 20° Mar 16 Mar 10 Mar 5 Mar 1 Feb 26 Feb 22 Feb 18 Feb 14 Feb 7
Last 24° Mar 25 Mar 21 Mar 18 Mar 16 Mar 13 Mar 11 Mar 8 Mar 5 Mar 1
Last 28° Apr 11 Apr 6 Apr 3 Mar 30 Mar 28 Mar 25 Mar 21 Mar 18 Mar 13
Last 32° Apr 17 Apr 13 Apr 10 Apr 7 Apr 5 Apr 3 Mar 31 Mar 28 Mar 24
Last 36° Apr 28 Apr 23 Apr 20 Apr 18 Apr 15 Apr 12 Apr 10 Apr 6 Apr 2

ℹ️ How to read these charts for the fall

As summer ends in Mt Vernon, IN, 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 19, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By October 28, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By November 7, 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 November 7 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 26 Dec 3 Dec 8 Dec 12 Dec 16 Dec 20 Dec 24 Dec 30 Jan 6
First 20° Nov 13 Nov 20 Nov 25 Nov 30 Dec 4 Dec 8 Dec 13 Dec 18 Dec 25
First 24° Nov 2 Nov 8 Nov 13 Nov 17 Nov 21 Nov 25 Nov 29 Dec 4 Dec 10
First 28° Oct 25 Oct 30 Nov 3 Nov 6 Nov 9 Nov 12 Nov 15 Nov 19 Nov 24
First 32° Oct 13 Oct 19 Oct 22 Oct 25 Oct 28 Oct 31 Nov 3 Nov 7 Nov 12
First 36° Sep 30 Oct 5 Oct 9 Oct 13 Oct 16 Oct 19 Oct 23 Oct 26 Nov 1

📍 Frost Dates for other nearby locations

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