Did a Training/Beach dive with son, after a 30+min swim we located a small ledge in 20', water was cold, and murky as shmit (3'-4' vis), and the overcast did nothing to help us...we saw the shadow of quite a few nice fish, but passed the shots due to the poor conditions, aside from getting bumped by a few tarpon, and getting taxed by a 4+foot cuda (16" go' my son shot, snatched right off my stringer:head) my son managed to nail a nice hog, a new personal best for beach dive:martial
, 1.5 might be just fine, but maybe it won't...really depends on your cold tolerence...my son has a 3mm nylon both sides and he's usually cold...here's a tip we recently discovered we got a wool (keeps you warm even when wet) long john type top he puts on followed by wetsuit and he says it makes a huge difference. If your 1.5 is open cell (non nylon) inside and fits snug it should keep you pretty warm, my suit (Spiros) is opencell and its amazingly warm compared to my sons