UA 604 then UA 3237 at Houston
San Francisco → Houston → Mc Allen
Timetable, Houston time
06:32UA 604 from San Francisco at the gate
19:45UA 3237 to Mc Allen leaves the gate
13 h 13 apart on the timetable
UA 3237 leaves 13 h 13 after UA 604 arrives on the timetable: more than half a day, so not a connection we count.