While we are at it, let's also set 7pm to be when the sun sets! We just need all clocks to simply adjust by lengthen and contracting time units as needed! Sounds simple to me.
Plus think of all the new types of math problems we can give to high-school math students!
This is how Japanese time used to work. The hours would be longer in the summer and shorter in the winter. Good for roughly arranging local schedules when you only have relatively basic timekeeping.