I would do it. My dive partner (wife) would never do it. She wears about the same amount of neoprene that you have on in 78deg F water:-d I dive the same place in a shorty. I am hot-natured though. Must be the Doxa on my wrist.............;-)Yep, it's always cold in the Monterey Bay. 50 deg (10 deg C) year round.