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