OMG....You are describing my LO to a tee. At just about 2 mnths she did the same thing. She is now 13 weeks and still cries off and on. I have two ideas....Either she is just now aware of the temp change (I, like you didn't do anything different, she just started crying one day), so I make an extra effort to keep her held in her towel longer to absorb the water that is possibly making her cold when I put on her diaper. Sometimes this works, sometimes it doesn't. The second reason may be that she doesn't want to get out. I think this is it. She understands now that I have the ability to vary the amount of time she's in there, so she's upset when it's done. My LO loves her bath and splashes like crazy. I try to distract her by singing. Again, sometimes this works, sometimes it doesn't. If she's really crying I quickly put the diaper on and then hold her. Once she's stopped (almost immediately) I tell her "we just have to get dressed now", and try to continue. It usually works....I follow that with a massage with lotion and she gets quite relaxed.