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