Late night is when the worst dysphoria has struck for me, from when I was 12 onwards. Even if it eased for a while, I went into denial and everything, it would be 3 am with full force insomnia, and I'd feel really, really dysphoric. I think you're more aware of your body when you're trying to relax. Especially if you're failing.
Actually, my worst memories of dysphoria take place between midnight and 4 am. I'd get these episodes which were so... psychotic. Sleep deprived and frustrated, struggling with denial, socially isolated... I'd practically lose my mind. I'd go into detail, but... no one wants to hear about that crap. Plus it's probably triggering in a million different ways.