AA 2522 then WN 4578 at San Francisco
Dallas-Fort Worth → San Francisco → Denver
Timetable, San Francisco time
23:06AA 2522 from Dallas-Fort Worth at the gate
05:50WN 4578 to Denver leaves the gate
6 h 44 apart on the timetable, overnight
The last days
AA 2522 and WN 4578 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.