Big Bend in the summer??? We did it two years ago during the Christmas break. Netted temps anywhere from the high 90's to the low 30's with a little rain thrown in. The trails though...
Close enough in Houston.
https://www.nps.gov/bibe/planyourvisit/weather.htm
Nov 1, 2018 - Automated weather station readings throughout the Big Bend area. ... The table below is based on average temperatures and ... Try to avoid mid-march (spring break) unless you have reservations for accommodations.