Frost Dates: First and last frost dates for Amistad Dam, TX
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 30. 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 19, 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° | Dec 26 | -- | -- | -- | -- | -- | -- | -- | -- |
| Last 20° | Jan 21 | Jan 11 | Jan 1 | -- | -- | -- | -- | -- | -- |
| Last 24° | Feb 11 | Feb 1 | Jan 24 | Jan 17 | Jan 10 | Jan 1 | Dec 17 | -- | -- |
| Last 28° | Feb 25 | Feb 16 | Feb 9 | Feb 2 | Jan 27 | Jan 21 | Jan 12 | Dec 28 | -- |
| Last 32° | Mar 12 | Mar 1 | Feb 22 | Feb 16 | Feb 10 | Feb 4 | Jan 28 | Jan 21 | Jan 8 |
| Last 36° | Mar 30 | Mar 22 | Mar 16 | Mar 11 | Mar 6 | Mar 2 | Feb 25 | Feb 19 | Feb 11 |
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 22.
- There is a 50% chance of being hit by a 32° frost starting around December 6
- You have a 80% chance of seeing 32° by December 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° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| First 20° | Dec 30 | Jan 10 | Jan 22 | -- | -- | -- | -- | -- | -- |
| First 24° | Dec 14 | Dec 23 | Dec 31 | Jan 7 | Jan 14 | Jan 24 | -- | -- | -- |
| First 28° | Dec 4 | Dec 13 | Dec 19 | Dec 25 | Dec 31 | Jan 6 | Jan 13 | Jan 27 | -- |
| First 32° | Nov 14 | Nov 22 | Nov 27 | Dec 2 | Dec 6 | Dec 10 | Dec 15 | Dec 21 | Dec 30 |
| First 36° | Nov 5 | Nov 11 | Nov 15 | Nov 18 | Nov 22 | Nov 25 | Nov 29 | Dec 3 | Dec 9 |
Data is provided by the NOAA National Centers for Environmental Information.