Frost Dates: First and last frost dates for la barge, 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 July 29. 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 4, so we don't dare plant that early. We wait a few days and by July 14 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 16 | May 9 | May 4 | Apr 29 | Apr 25 | Apr 21 | Apr 17 | Apr 11 | Apr 4 |
Last 20° | May 23 | May 17 | May 13 | May 9 | May 6 | May 3 | Apr 29 | Apr 25 | Apr 20 |
Last 24° | Jun 9 | Jun 2 | May 28 | May 24 | May 19 | May 15 | May 11 | May 5 | Apr 28 |
Last 28° | Jun 24 | Jun 16 | Jun 11 | Jun 6 | Jun 2 | May 29 | May 24 | May 19 | May 11 |
Last 32° | Jul 12 | Jul 6 | Jul 2 | Jun 28 | Jun 25 | Jun 21 | Jun 18 | Jun 13 | Jun 7 |
Last 36° | Jul 29 | Jul 24 | Jul 20 | Jul 17 | Jul 14 | Jul 11 | Jul 8 | Jul 4 | Jun 29 |
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 14.
- There is a 50% chance of being hit by a 32° frost starting around August 26
- You have a 80% chance of seeing 32° by September 6
- 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 17 | Sep 24 | Sep 29 | Oct 3 | Oct 7 | Oct 11 | Oct 15 | Oct 20 | Oct 27 |
First 20° | Sep 12 | Sep 17 | Sep 21 | Sep 24 | Sep 27 | Sep 30 | Oct 3 | Oct 7 | Oct 12 |
First 24° | Sep 1 | Sep 6 | Sep 10 | Sep 13 | Sep 16 | Sep 20 | Sep 23 | Sep 27 | Oct 2 |
First 28° | Aug 20 | Aug 26 | Aug 31 | Sep 4 | Sep 7 | Sep 11 | Sep 15 | Sep 19 | Sep 26 |
First 32° | Aug 8 | Aug 14 | Aug 19 | Aug 22 | Aug 26 | Aug 29 | Sep 2 | Sep 6 | Sep 13 |
First 36° | Aug 2 | Aug 6 | Aug 10 | Aug 12 | Aug 15 | Aug 18 | Aug 21 | Aug 24 | Aug 29 |
Data is provided by the NOAA National Centers for Environmental Information.