In Houston the nighttime low temperatures are increasing rapidly, but the high temperatures are staying about the same.
Low temperatures are increasing the most in February and March, both at about 0.7'F per decade. Before 1970 lows were below 53'F most of the time. After 1985, lows were about 53'F most of the time. The highs showed no change.
In June and October Houston's high temperatures are dropping at 0.2'F per decade. The lows are still rising.
February is interesting because the high temperatures appear to be rising in jumps. The lows appeared to be dropping before 1965, but rising rapidly after 1976.