UA 3891 then UA 5209 at Houston
CWF → Houston → San Francisco
Timetable, Houston time
00:31UA 3891 from CWF at the gate
07:00UA 5209 to San Francisco leaves the gate
6 h 29 apart on the timetable
The last days
UA 3891 and UA 5209 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.