Frost Dates: First and last frost dates for silver lake rs, or

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 17, so we don't dare plant that early. We wait a few days and by July 25 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 16 May 7 Apr 30 Apr 24 Apr 18 Apr 13 Apr 7 Mar 31 Mar 22
Last 20° Jun 16 Jun 6 May 30 May 23 May 17 May 12 May 5 Apr 28 Apr 18
Last 24° Jul 8 Jun 30 Jun 23 Jun 18 Jun 13 Jun 8 Jun 3 May 28 May 19
Last 28° Jul 28 Jul 20 Jul 14 Jul 9 Jul 5 Jun 30 Jun 26 Jun 20 Jun 12
Last 32° Aug 3 Jul 28 Jul 24 Jul 20 Jul 17 Jul 14 Jul 10 Jul 6 Jun 30
Last 36° Aug 4 Aug 1 Jul 29 Jul 27 Jul 25 Jul 22 Jul 20 Jul 17 Jul 14

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for silver lake rs, or 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 July 30, and by August 17 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 2.
  2. There is a 50% chance of being hit by a 32° frost starting around August 9
  3. You have a 80% chance of seeing 32° by August 17
  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 25 Oct 3 Oct 9 Oct 14 Oct 18 Oct 23 Oct 28 Nov 3 Nov 11
First 20° Sep 9 Sep 17 Sep 22 Sep 27 Oct 1 Oct 5 Oct 10 Oct 15 Oct 23
First 24° Aug 21 Aug 29 Sep 4 Sep 9 Sep 13 Sep 18 Sep 23 Sep 29 Oct 7
First 28° Aug 3 Aug 10 Aug 14 Aug 18 Aug 22 Aug 26 Aug 30 Sep 4 Sep 10
First 32° Jul 30 Aug 2 Aug 5 Aug 7 Aug 9 Aug 12 Aug 14 Aug 17 Aug 21
First 36° Jul 31 Aug 1 Aug 2 Aug 3 Aug 4 Aug 5 Aug 6 Aug 7 Aug 9

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