Frost Dates: First and last frost dates for Mc Nary, AZ

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 June 27, 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 June 4, 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 22 Apr 13 Apr 7 Apr 2 Mar 27 Mar 22 Mar 17 Mar 10 Mar 1
Last 20° May 7 Apr 28 Apr 22 Apr 17 Apr 12 Apr 7 Apr 2 Mar 27 Mar 19
Last 24° May 20 May 13 May 7 May 3 Apr 29 Apr 25 Apr 20 Apr 15 Apr 8
Last 28° Jun 8 Jun 1 May 27 May 22 May 18 May 14 May 10 May 5 Apr 28
Last 32° Jun 17 Jun 11 Jun 7 Jun 3 May 31 May 27 May 23 May 19 May 13
Last 36° Jun 27 Jun 22 Jun 19 Jun 16 Jun 13 Jun 10 Jun 7 Jun 4 May 30

ℹ️ How to read these charts for the fall

As summer ends in Mc Nary, AZ, 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 24, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By October 4, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By October 15, 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 15 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 27 Nov 2 Nov 7 Nov 11 Nov 15 Nov 19 Nov 23 Nov 27 Dec 4
First 20° Oct 20 Oct 25 Oct 29 Nov 1 Nov 4 Nov 7 Nov 10 Nov 14 Nov 20
First 24° Oct 12 Oct 18 Oct 22 Oct 25 Oct 28 Nov 1 Nov 4 Nov 8 Nov 14
First 28° Oct 2 Oct 7 Oct 11 Oct 14 Oct 17 Oct 20 Oct 23 Oct 27 Nov 1
First 32° Sep 18 Sep 24 Sep 28 Oct 1 Oct 4 Oct 7 Oct 11 Oct 15 Oct 20
First 36° Sep 2 Sep 8 Sep 13 Sep 16 Sep 20 Sep 23 Sep 27 Oct 1 Oct 7

📍 Frost Dates for other nearby locations

Or enter a new zipcode:

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