You are way off on your perception of latest sunrise and earliest sunset in Seattle:
https://www.timeanddate.com/sun/usa/seattle?month=12&year=20...
https://www.timeanddate.com/sun/usa/seattle?month=12&year=20...
But keep in mind that the definitions of sunrise and sunset here do not include dawn and dusk -- at 4 PM, the sun has _completely_ set, which means that at 3 PM, it's already well into starting to set.