UA 3870 then AC 4530 at San Francisco
Xiamen → San Francisco → Sacramento
Timetable, San Francisco time
07:49UA 3870 from Xiamen at the gate
16:10AC 4530 to Sacramento leaves the gate
8 h 21 apart on the timetable
The last days
UA 3870 and AC 4530 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.