Frost Dates: First and last frost dates for Boca, 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 August 3, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around July 27, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before July 23, 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° May 12 May 5 Apr 30 Apr 26 Apr 22 Apr 18 Apr 14 Apr 9 Apr 2
Last 20° Jun 10 Jun 1 May 26 May 21 May 16 May 11 May 6 Apr 30 Apr 21
Last 24° Jun 30 Jun 21 Jun 14 Jun 8 Jun 3 May 29 May 23 May 16 May 7
Last 28° Jul 22 Jul 15 Jul 11 Jul 6 Jul 2 Jun 28 Jun 24 Jun 19 Jun 12
Last 32° Aug 1 Jul 28 Jul 25 Jul 22 Jul 19 Jul 17 Jul 14 Jul 11 Jul 7
Last 36° Aug 3 Aug 1 Jul 30 Jul 29 Jul 27 Jul 26 Jul 25 Jul 23 Jul 21

ℹ️ How to read these charts for the fall

As summer ends in Boca, 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 3, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By August 8, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By August 13, 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 August 13 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 1 Oct 9 Oct 15 Oct 20 Oct 25 Oct 30 Nov 4 Nov 10 Nov 18
First 20° Sep 15 Sep 22 Sep 27 Oct 1 Oct 5 Oct 9 Oct 14 Oct 19 Oct 26
First 24° Aug 18 Aug 28 Sep 4 Sep 9 Sep 15 Sep 20 Sep 26 Oct 3 Oct 12
First 28° Aug 3 Aug 10 Aug 15 Aug 19 Aug 23 Aug 27 Aug 31 Sep 5 Sep 12
First 32° Jul 31 Aug 3 Aug 5 Aug 6 Aug 8 Aug 9 Aug 11 Aug 13 Aug 16
First 36° Jul 31 Aug 1 Aug 2 Aug 3 Aug 4 Aug 5 Aug 6 Aug 7 Aug 9

📍 Frost Dates for other nearby locations

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