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

How to read these charts for the spring
As the growing season approaches, the days get longer, the weather begins to warm up, and the nights start being less cold. You're still getting frost, but the chance of nightly frosts gets less and less with each passing day. Eventually, the frost stops, and this is when your tender plants are fully safe. So, how do you plan for this? The probabilities on this page help you assess your risk of frost on any given day.

What's a safe temperature for tender plants? When the nightly temperature falls, frost can form, even above 32°, because the air is colder high above the ground and the frost can form up there and then fall down onto your garden and do some damage, even if it's 36° on the ground. So many factors come into play, including wind, concrete, houses, trees and other structures, etc etc etc. Because of all this, you might want to consider 36° as "the danger zone".

In your average springtime, you have a 90% chance that there will be no 36° nights by August 4. In other words, you can pretty much count on being safe from frost by that day. But we want to get those tomatoes in the ground as soon as possible, right? We see that there's still an 80% chance of 36° on July 12, so we don't dare plant that early. We wait a few days and by July 21 we are at the 50/50 point. At this point, we are close and we can start watching the weather forecast. If the upcoming week's forecast doesn't show below 40°, then it's probably okay to risk planting out your plants.

In the Spring
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
Last 16° May 19 May 10 May 4 Apr 29 Apr 24 Apr 19 Apr 14 Apr 8 Mar 30
Last 20° Jun 10 Jun 1 May 26 May 21 May 15 May 10 May 5 Apr 28 Apr 19
Last 24° Jun 29 Jun 20 Jun 13 Jun 8 Jun 3 May 28 May 23 May 16 May 8
Last 28° Jul 23 Jul 13 Jul 6 Jun 30 Jun 24 Jun 18 Jun 12 Jun 5 May 26
Last 32° Jul 31 Jul 23 Jul 18 Jul 13 Jul 8 Jul 4 Jun 29 Jun 23 Jun 16
Last 36° Aug 4 Jul 30 Jul 27 Jul 24 Jul 21 Jul 18 Jul 15 Jul 12 Jul 7

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for Bridgeport, CA start to go down, and therefore every day that goes by increases the chance that you'll get frost. Your risk of frost really begins around August 2, and by September 1 you're almost certain to have received at least one frost event.

The charts on this page show the probabilities of receiving a certain temperature on a certain day. Some examples that might help:

  1. You have a small 20% chance of getting 32° by August 8.
  2. There is a 50% chance of being hit by a 32° frost starting around August 20
  3. You have a 80% chance of seeing 32° by September 1
  4. Said another way, you have a 1 in 5 chance at making it to that day without a 32° night.
In the Fall
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
First 16° Sep 24 Oct 1 Oct 6 Oct 10 Oct 15 Oct 19 Oct 23 Oct 28 Nov 4
First 20° Sep 11 Sep 17 Sep 22 Sep 26 Sep 30 Oct 3 Oct 7 Oct 12 Oct 18
First 24° Aug 26 Sep 3 Sep 8 Sep 13 Sep 18 Sep 22 Sep 27 Oct 3 Oct 11
First 28° Aug 11 Aug 18 Aug 23 Aug 28 Sep 1 Sep 5 Sep 10 Sep 15 Sep 22
First 32° Aug 2 Aug 8 Aug 13 Aug 17 Aug 20 Aug 24 Aug 27 Sep 1 Sep 7
First 36° Jul 31 Aug 3 Aug 6 Aug 9 Aug 11 Aug 13 Aug 16 Aug 19 Aug 23

Frost Dates for other nearby locations
  • Bodie Ca St Historic Park, CA
  • Hetch Hetchy, CA
  • Yosemite Park Hq, CA
  • Cherry Valley Dam, CA
  • So Entr Yosemite Np, CA
  • Yerington, NV
  • Minden, NV
  • Twin Lakes, CA
  • South Lake Tahoe Ap, CA
  • Huntington Lake, CA

    Or enter a new zipcode:

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