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