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