Frost Dates: First and last frost dates for Couderay, WI

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 8, 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 28, 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 30 Apr 23 Apr 19 Apr 15 Apr 11 Apr 7 Apr 3 Mar 29 Mar 23
Last 20° May 16 May 8 May 3 Apr 28 Apr 23 Apr 19 Apr 14 Apr 8 Apr 1
Last 24° May 26 May 20 May 15 May 11 May 7 May 3 Apr 29 Apr 24 Apr 17
Last 28° Jun 11 Jun 4 May 30 May 26 May 22 May 19 May 15 May 10 May 3
Last 32° Jun 23 Jun 16 Jun 11 Jun 7 Jun 3 May 30 May 26 May 21 May 14
Last 36° Jul 8 Jun 29 Jun 23 Jun 18 Jun 13 Jun 8 Jun 3 May 28 May 19

ℹ️ How to read these charts for the fall

As summer ends in Couderay, WI, 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 1, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By September 13, 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 14 Oct 19 Oct 23 Oct 27 Oct 30 Nov 2 Nov 5 Nov 9 Nov 15
First 20° Sep 27 Oct 4 Oct 8 Oct 12 Oct 16 Oct 20 Oct 24 Oct 29 Nov 4
First 24° Sep 14 Sep 20 Sep 25 Sep 28 Oct 2 Oct 5 Oct 9 Oct 13 Oct 19
First 28° Sep 3 Sep 10 Sep 15 Sep 19 Sep 23 Sep 27 Oct 1 Oct 6 Oct 13
First 32° Aug 26 Sep 1 Sep 5 Sep 9 Sep 13 Sep 16 Sep 20 Sep 25 Oct 1
First 36° Aug 17 Aug 23 Aug 28 Sep 1 Sep 5 Sep 8 Sep 12 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.