Sleeping nude for me is a year round thing. I can't stand fighting clothes when I toss and turn in bed. Being cooler in the summer is definitely a bonus though. As for the winter time I just set the thermostat at 69 F and I'm good.
I try to do so whenever I can. However, there are times that when I crawl under the sheets nude and get an erection; sometimes it requires "relief", sometimes not. Sure feels better sleeping nude, though!!