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