F8 1846 then UA 3036 at San Francisco
Vancouver → San Francisco → Chicago O'Hare
Timetable, San Francisco time
08:30F8 1846 from Vancouver at the gate
12:27UA 3036 to Chicago O'Hare leaves the gate
3 h 57 apart on the timetable
The last days
F8 1846 and UA 3036 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.