Frost Dates: First and last frost dates for Chester, 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 22, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around July 3, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before June 21, 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 11 Apr 1 Mar 25 Mar 19 Mar 14 Mar 8 Mar 3 Feb 24 Feb 14
Last 20° Apr 29 Apr 20 Apr 13 Apr 7 Apr 2 Mar 28 Mar 22 Mar 16 Mar 6
Last 24° May 19 May 12 May 7 May 2 Apr 28 Apr 24 Apr 20 Apr 15 Apr 7
Last 28° Jun 8 Jun 1 May 28 May 23 May 20 May 16 May 12 May 7 Apr 30
Last 32° Jul 2 Jun 25 Jun 20 Jun 16 Jun 12 Jun 8 Jun 4 May 30 May 23
Last 36° Jul 22 Jul 16 Jul 11 Jul 7 Jul 3 Jun 30 Jun 26 Jun 21 Jun 14

ℹ️ How to read these charts for the fall

As summer ends in Chester, 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 31, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By September 14, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By September 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 September 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 4 Nov 12 Nov 17 Nov 22 Nov 26 Nov 30 Dec 4 Dec 10 Dec 17
First 20° Oct 22 Oct 29 Nov 3 Nov 8 Nov 12 Nov 16 Nov 21 Nov 26 Dec 3
First 24° Oct 3 Oct 9 Oct 14 Oct 18 Oct 22 Oct 26 Oct 30 Nov 4 Nov 11
First 28° Sep 15 Sep 22 Sep 27 Oct 1 Oct 5 Oct 9 Oct 13 Oct 18 Oct 24
First 32° Aug 24 Aug 31 Sep 5 Sep 9 Sep 14 Sep 18 Sep 22 Sep 27 Oct 4
First 36° Aug 3 Aug 11 Aug 17 Aug 23 Aug 27 Sep 1 Sep 6 Sep 12 Sep 20

📍 Frost Dates for other nearby locations

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