CA 985 then WN 137 at San Francisco
Beijing → San Francisco → Denver
Timetable, San Francisco time
09:30CA 985 from Beijing at the gate
14:15WN 137 to Denver leaves the gate
4 h 45 apart on the timetable
The last days
CA 985 and WN 137 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.