Pretty normal it seems for the smaller Norcold. A fan in the rear is suppose to help, but I haven't really noticed the difference with a fan yet.
I have the same problem any time the camper gets above low 80s. Solved the problem by putting 3 frozen water bottles in the freezer and 3 in the fridge. The ones in the fridge will last a couple of days but I change them out with the ones in the freezer each night when I go to bed. Since I started doing this in the summertime, I can usually hold the fridge about 37* when not going in it much and 40* with use.