Frost Dates: First and last frost dates for Leavenworth, KS

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 12, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around April 26, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before April 15, 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 26 Mar 17 Mar 11 Mar 5 Feb 28 Feb 23 Feb 18 Feb 12 Feb 3
Last 20° Apr 3 Mar 26 Mar 21 Mar 16 Mar 11 Mar 7 Mar 2 Feb 24 Feb 16
Last 24° Apr 14 Apr 7 Apr 1 Mar 28 Mar 24 Mar 20 Mar 15 Mar 10 Mar 3
Last 28° Apr 17 Apr 13 Apr 10 Apr 7 Apr 4 Apr 2 Mar 30 Mar 27 Mar 22
Last 32° Apr 27 Apr 22 Apr 19 Apr 16 Apr 14 Apr 11 Apr 8 Apr 5 Mar 31
Last 36° May 12 May 6 May 2 Apr 29 Apr 26 Apr 23 Apr 19 Apr 15 Apr 10

ℹ️ How to read these charts for the fall

As summer ends in Leavenworth, KS, 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 5, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By October 16, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By October 27, 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 27 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 10 Nov 17 Nov 22 Nov 27 Dec 1 Dec 5 Dec 9 Dec 15 Dec 22
First 20° Nov 5 Nov 11 Nov 15 Nov 19 Nov 22 Nov 26 Nov 29 Dec 3 Dec 9
First 24° Oct 24 Oct 30 Nov 3 Nov 7 Nov 10 Nov 13 Nov 17 Nov 21 Nov 27
First 28° Oct 16 Oct 22 Oct 26 Oct 30 Nov 2 Nov 5 Nov 9 Nov 13 Nov 19
First 32° Sep 29 Oct 5 Oct 9 Oct 12 Oct 16 Oct 19 Oct 23 Oct 27 Nov 1
First 36° Sep 23 Sep 27 Oct 1 Oct 4 Oct 6 Oct 9 Oct 12 Oct 15 Oct 20

📍 Frost Dates for other nearby locations

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