It’s not just because it’s associated with summer, quite the opposite: many of us just feel that sunset 30 minutes after work in the winter will be less depressing than the sun setting while we’re in the office. And then even more so during the days where it moves from 5:30 to 6:30, that’s enough to actually get out and do an activity.
I get that there are good reasons for morning light too, I’m just saying that I don’t think it’s just an association with summer.