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