Frost Dates: First and last frost dates for Houston Hobby, 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 26. 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 January 31, so we don't dare plant that early. We wait a few days and by February 22 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 25 | -- | -- | -- | -- | -- | -- | -- | -- |
| Last 20° | Jan 19 | Jan 4 | -- | -- | -- | -- | -- | -- | -- |
| Last 24° | Feb 20 | Feb 4 | Jan 22 | Jan 7 | Dec 15 | -- | -- | -- | -- |
| Last 28° | Mar 4 | Feb 18 | Feb 8 | Jan 30 | Jan 21 | Jan 10 | Dec 25 | -- | -- |
| Last 32° | Mar 18 | Mar 5 | Feb 24 | Feb 16 | Feb 8 | Feb 1 | Jan 24 | Jan 15 | Jan 2 |
| Last 36° | Mar 26 | Mar 15 | Mar 7 | Feb 28 | Feb 22 | Feb 15 | Feb 8 | Jan 31 | Jan 20 |
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 28.
- There is a 50% chance of being hit by a 32° frost starting around December 20
- You have a 80% chance of seeing 32° by January 11
- 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° | Jan 5 | -- | -- | -- | -- | -- | -- | -- | -- |
| First 20° | Jan 6 | Jan 23 | -- | -- | -- | -- | -- | -- | -- |
| First 24° | Dec 19 | Jan 5 | Jan 20 | Feb 4 | Mar 2 | -- | -- | -- | -- |
| First 28° | Dec 3 | Dec 17 | Dec 28 | Jan 7 | Jan 17 | Jan 30 | Feb 21 | -- | -- |
| First 32° | Nov 17 | Nov 28 | Dec 6 | Dec 13 | Dec 20 | Dec 26 | Jan 2 | Jan 11 | Jan 22 |
| First 36° | Nov 9 | Nov 17 | Nov 22 | Nov 27 | Dec 2 | Dec 6 | Dec 11 | Dec 17 | Dec 25 |
Data is provided by the NOAA National Centers for Environmental Information.