Frost Dates: First and last frost dates for Mineral, CA

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 30, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around July 15, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before July 5, 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 26 Apr 14 Apr 5 Mar 29 Mar 22 Mar 16 Mar 8 Feb 28 Feb 16
Last 20° May 11 May 1 Apr 24 Apr 17 Apr 12 Apr 6 Mar 31 Mar 24 Mar 14
Last 24° May 22 May 16 May 11 May 7 May 4 Apr 30 Apr 26 Apr 22 Apr 15
Last 28° Jun 21 Jun 14 Jun 9 Jun 5 Jun 2 May 29 May 25 May 20 May 13
Last 32° Jul 18 Jul 10 Jul 5 Jul 1 Jun 27 Jun 22 Jun 18 Jun 13 Jun 5
Last 36° Jul 30 Jul 25 Jul 21 Jul 18 Jul 15 Jul 12 Jul 9 Jul 5 Jun 30

ℹ️ How to read these charts for the fall

As summer ends in Mineral, CA, 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 August 20, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By September 5, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By September 21, 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 21 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 3 Nov 12 Nov 19 Nov 25 Nov 30 Dec 6 Dec 11 Dec 18 Dec 28
First 20° Oct 26 Nov 2 Nov 6 Nov 10 Nov 14 Nov 18 Nov 21 Nov 26 Dec 2
First 24° Oct 6 Oct 13 Oct 17 Oct 21 Oct 25 Oct 28 Nov 1 Nov 6 Nov 12
First 28° Sep 9 Sep 15 Sep 20 Sep 24 Sep 27 Oct 1 Oct 5 Oct 9 Oct 16
First 32° Aug 12 Aug 20 Aug 26 Sep 1 Sep 5 Sep 10 Sep 15 Sep 21 Sep 29
First 36° Aug 1 Aug 5 Aug 8 Aug 10 Aug 12 Aug 15 Aug 17 Aug 20 Aug 24

📍 Frost Dates for other nearby locations

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