Frost Dates: First and last frost dates for Newark, 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 March 15, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around January 30, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before December 22, 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° -- -- -- -- -- -- -- -- --
Last 20° -- -- -- -- -- -- -- -- --
Last 24° -- -- -- -- -- -- -- -- --
Last 28° Jan 8 Dec 25 -- -- -- -- -- -- --
Last 32° Jan 31 Jan 20 Jan 11 Jan 1 Dec 15 -- -- -- --
Last 36° Mar 15 Feb 28 Feb 17 Feb 8 Jan 30 Jan 20 Jan 8 Dec 22 --

ℹ️ How to read these charts for the fall

As summer ends in Newark, 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 December 17, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By January 24, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By --, 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 -- 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° -- -- -- -- -- -- -- -- --
First 20° -- -- -- -- -- -- -- -- --
First 24° -- -- -- -- -- -- -- -- --
First 28° Dec 20 Jan 4 -- -- -- -- -- -- --
First 32° Dec 6 Dec 17 Dec 27 Jan 7 Jan 24 -- -- -- --
First 36° Nov 21 Dec 1 Dec 9 Dec 16 Dec 23 Dec 30 Jan 8 Jan 25 --

📍 Frost Dates for other nearby locations

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