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 27. 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 30, so we don't dare plant that early. We wait a few days and by May 11 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. If conditions change and a surprise frost does threaten, there's always things you can do to protect plants from frost.
Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
---|---|---|---|---|---|---|---|---|---|
Last 16° | Mar 30 | Mar 22 | Mar 16 | Mar 12 | Mar 7 | Mar 3 | Feb 26 | Feb 21 | Feb 13 |
Last 20° | Apr 7 | Apr 2 | Mar 30 | Mar 27 | Mar 24 | Mar 21 | Mar 18 | Mar 14 | Mar 9 |
Last 24° | Apr 19 | Apr 15 | Apr 11 | Apr 8 | Apr 5 | Apr 3 | Mar 31 | Mar 27 | Mar 23 |
Last 28° | May 2 | Apr 27 | Apr 22 | Apr 19 | Apr 15 | Apr 12 | Apr 8 | Apr 4 | Mar 29 |
Last 32° | May 16 | May 11 | May 8 | May 5 | May 2 | Apr 29 | Apr 26 | Apr 22 | Apr 18 |
Last 36° | May 27 | May 21 | May 17 | May 14 | May 11 | May 7 | May 4 | Apr 30 | Apr 24 |
The charts on this page show the probabilities of receiving a certain temperature on a certain day. Some examples that might help:
Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
---|---|---|---|---|---|---|---|---|---|
First 16° | Nov 12 | Nov 19 | Nov 24 | Nov 29 | Dec 2 | Dec 6 | Dec 11 | Dec 16 | Dec 23 |
First 20° | Oct 27 | Nov 4 | Nov 9 | Nov 14 | Nov 18 | Nov 23 | Nov 27 | Dec 3 | Dec 10 |
First 24° | Oct 15 | Oct 22 | Oct 27 | Oct 31 | Nov 5 | Nov 9 | Nov 13 | Nov 18 | Nov 25 |
First 28° | Oct 8 | Oct 14 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Oct 31 | Nov 4 | Nov 9 |
First 32° | Sep 29 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 27 |
First 36° | Sep 20 | Sep 24 | Sep 27 | Sep 30 | Oct 2 | Oct 4 | Oct 7 | Oct 10 | Oct 14 |
Now that you know your frost dates, use our Garden Planting Calendar for Ripley, WV to know when to sow and transplant your various vegetable plants!
Data is provided by the NOAA National Centers for Environmental Information. Photography by Garden.org member TBGDN.