Frost Dates: First and last frost dates for Crested Butte, CO

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 3. 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 22, so we don't dare plant that early. We wait a few days and by July 27 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 11 May 7 May 3 May 1 Apr 28 Apr 25 Apr 22 Apr 19 Apr 15
Last 20° May 23 May 19 May 16 May 14 May 12 May 9 May 7 May 4 Apr 30
Last 24° Jun 22 Jun 15 Jun 9 Jun 4 May 31 May 27 May 22 May 17 May 9
Last 28° Jul 6 Jul 1 Jun 28 Jun 24 Jun 22 Jun 19 Jun 16 Jun 12 Jun 7
Last 32° Jul 31 Jul 25 Jul 21 Jul 18 Jul 15 Jul 11 Jul 8 Jul 4 Jun 28
Last 36° Aug 3 Aug 1 Jul 30 Jul 28 Jul 27 Jul 25 Jul 24 Jul 22 Jul 19

How to read these charts for the fall
As your growing season comes to an end, the nightly temperatures for Crested Butte, CO 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 31, and by August 25 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 4.
  2. There is a 50% chance of being hit by a 32° frost starting around August 15
  3. You have a 80% chance of seeing 32° by August 25
  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 23 Sep 29 Oct 2 Oct 6 Oct 9 Oct 12 Oct 15 Oct 19 Oct 24
First 20° Sep 13 Sep 17 Sep 21 Sep 23 Sep 26 Sep 28 Oct 1 Oct 4 Oct 9
First 24° Aug 28 Sep 3 Sep 8 Sep 11 Sep 15 Sep 18 Sep 22 Sep 26 Oct 2
First 28° Aug 18 Aug 23 Aug 27 Aug 30 Sep 2 Sep 5 Sep 8 Sep 11 Sep 16
First 32° Jul 31 Aug 4 Aug 8 Aug 12 Aug 15 Aug 18 Aug 21 Aug 25 Aug 30
First 36° Jul 30 Jul 31 Aug 2 Aug 3 Aug 4 Aug 5 Aug 6 Aug 8 Aug 9

Frost Dates for other nearby locations
  • Gunnison, CO
  • Taylor Park, CO
  • Blue Mesa Lake, CO
  • Cochetopa Creek, CO
  • Meredith, CO
  • Twin Lakes Reservoir, CO
  • Paonia, CO
  • Sugarloaf Rsvr, CO
  • Cimarron, CO
  • Glenwood Spgs #2, CO

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