Hi Lily! We live up here so I can't speak to the adjustment part! But as far as clothes for the dorm, when my daughter was there, her dorm room was overly hot. But generally, bring clothes to dress in layers....long sleeve shirts, sweaters/sweatshirts (even just a few sweatshirts or hoodies that you can wear over different shirts would cut down on the amount you need to bring), a few pairs of "tall" socks if you are used to just wearing ankle or no-show socks. Bring a warm coat, or if you don't want to bring one, plan on buying one sometime in September. The mall is close, as is a Target, etc. Even though both my girls did not like boots, a pair of warm boots is necessary. Again those can be purchased up here. I know one of mine liked Uggs, the other wanted something more waterproof. Gloves/hat/scarf (nice for wrapping around your face while walking the windy quarter mile!) - whatever you prefer, not sure what college kids wear these days! You probably won't be able to find those in Texas before you come up, so again purchasing up here would work. Many stores will have winter wear out already the end of August when you move into your dorm. Unfortunately up here the summer stuff is usually out of the stores just about the time you want to buy new shorts for the end of the summer!
The classrooms seemed to be a range of overly warm in the winter, to chilly!
Good luck! My son is also going to RIT next year - for Film.