Becca love, you ask the most interesting questions lol
Well it's 31 degrees C here right now (88 F) and I'm wearing a loose sarong with no bra, but I would feel rather uncomfortable being completely naked. Funny it didn't used to bother me too much, and I mostly slept nude. Now I usually wear at least a PJ top or nightgown and panties to bed. I do get naked for sex of course, but most of the time I put my jammies back on afterward. I just feel so... exposed.
I think it may be like Jerica said- even though my body is now female shaped thanks to hormones, being completely naked is just too much of a reminder that I'm not yet complete. I'm interested to see if that attitude changes after SRS.