3 month old bedtime

How should I dress my three month old for bed? Our bedroom is usually a bit warmer than the rest of the house which we keep pretty cool. We do sleep with the ceiling fan on. He sleeps in a dock a tot in the pack n play. I’ve been putting him in footie long sleeve jammies but worried about him getting too hot. Should he be in just a onesie? Or is he fine in the jammies?