CZ 1637 then AS 758 at San Francisco
Philadelphia → San Francisco → Seattle
Timetable, San Francisco time
20:33CZ 1637 from Philadelphia at the gate
20:46AS 758 to Seattle leaves the gate
13 min apart on the timetable
The last days
CZ 1637 and AS 758 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.