Don't know how long you've been in the Boerne, TX area, but last winter we had some 24 degree nights. The year before that it got down into the teens on several occasions.
The thing about this past winter is that on a number of days it barely got above freezing. And the nights during that time were in the low 20's. That is what you have to worry about.
Wow! That almost sounds good today since it was 103 in San Antonio.
2009 Newmar 42 ft. Allstar 4188, Wheelchair Accessible, 400HP Cummins ISL, Allison 3000, Mastertow Dolly, '98 Riviera