Dang! 45 degrees in a 5mil??? That’s crazy! Here in SoCal we see temps in winter dip to around 48-54 degrees, and most can’t handle it with a 7mil, opting for a dry suit. I am considered a diver who runs hot. I sometimes dive in a 3mil during the summer when the water is in the upper 60’s. But I do start feeling the cold through my 7mil when the temp dips below 50. I’m not sure what the water temps are in the Mid West, but I’m sure someone will chime in soon. Dang!