WN 2159 then WN 425 at Denver
Kansas City → Denver → Seattle
Timetable, Denver time
12:10WN 2159 from Kansas City at the gate
18:15WN 425 to Seattle leaves the gate
6 h 05 apart on the timetable
The last days
WN 2159 and WN 425 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.