Frost Dates: First and last frost dates for black mtn, wy
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 5. 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 18, 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.
Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
---|---|---|---|---|---|---|---|---|---|
Last 16° | May 13 | May 9 | May 6 | May 3 | May 1 | Apr 29 | Apr 26 | Apr 23 | Apr 19 |
Last 20° | May 22 | May 18 | May 14 | May 12 | May 9 | May 6 | May 4 | Apr 30 | Apr 26 |
Last 24° | Jun 18 | Jun 10 | Jun 4 | May 30 | May 26 | May 21 | May 16 | May 10 | May 2 |
Last 28° | Jul 12 | Jul 6 | Jul 1 | Jun 27 | Jun 24 | Jun 20 | Jun 17 | Jun 12 | Jun 6 |
Last 32° | Jul 31 | Jul 26 | Jul 22 | Jul 18 | Jul 15 | Jul 12 | Jul 8 | Jul 4 | Jun 28 |
Last 36° | Aug 5 | Aug 1 | Jul 30 | Jul 27 | Jul 25 | Jul 23 | Jul 21 | Jul 18 | Jul 15 |
The charts on this page show the probabilities of receiving a certain temperature on a certain day. Some examples that might help:
- You have a small 20% chance of getting 32° by August 6.
- There is a 50% chance of being hit by a 32° frost starting around August 17
- You have a 80% chance of seeing 32° by August 27
- Said another way, you have a 1 in 5 chance at making it to that day without a 32° night.
Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
---|---|---|---|---|---|---|---|---|---|
First 16° | Sep 19 | Sep 25 | Sep 30 | Oct 4 | Oct 8 | Oct 11 | Oct 15 | Oct 20 | Oct 26 |
First 20° | Sep 7 | Sep 12 | Sep 16 | Sep 19 | Sep 21 | Sep 24 | Sep 27 | Sep 30 | Oct 5 |
First 24° | Aug 30 | Sep 5 | Sep 8 | Sep 12 | Sep 15 | Sep 18 | Sep 21 | Sep 25 | Sep 30 |
First 28° | Aug 9 | Aug 16 | Aug 21 | Aug 26 | Aug 30 | Sep 3 | Sep 7 | Sep 12 | Sep 19 |
First 32° | Aug 1 | Aug 6 | Aug 10 | Aug 13 | Aug 17 | Aug 20 | Aug 23 | Aug 27 | Sep 1 |
First 36° | Jul 30 | Aug 1 | Aug 3 | Aug 4 | Aug 5 | Aug 7 | Aug 8 | Aug 10 | Aug 12 |
Data is provided by the NOAA National Centers for Environmental Information.