On this date, July 8, back in 1939 a record high temperature and low temperature were both set on the same day at Houston Hobby Airport.
The high on July 8th 1939 was 105° while the low was 70°.
This is a diurnal range of 35°. Even today these two records still stand.
Based on current records this has only happened one other time June 20th, 1933 Houston Hobby Airport observed a record high of 99° and a record low of 66°.