"Closer to dawn than dusk" doesn't mean "at dawn", more like "before midday".
And yes, it is literally dawn in Finland during winter months, if we're gonna be pedantic about this. And you don't even need to go to into the polar circle. About halfway to 2/3rds up Finland would be enough for dawn to be around 11.30 during winter.
I would wager that for a lot people on Lemmy, 15.00 is closer to their wakeup time than bedtime.