UA 8264 then UA 581 at San Francisco
Houston → San Francisco → Cleveland
Timetable, San Francisco time
15:49UA 8264 from Houston at the gate
12:45UA 581 to Cleveland leaves the gate
20 h 56 apart on the timetable, overnight
UA 581 leaves 20 h 56 after UA 8264 arrives on the timetable: more than half a day, so not a connection we count.