UA 648 then UA 3912 at San Francisco
Newark → San Francisco → Houston
Timetable, San Francisco time
09:30UA 648 from Newark at the gatealso TP 8490, VA 8516, NZ 9121
23:00UA 3912 to Houston leaves the gate
13 h 30 apart on the timetable
UA 3912 leaves 13 h 30 after UA 648 arrives on the timetable: more than half a day, so not a connection we count.