It is 70-71 in water right now. Don't know where 78 degrees came from - maybe someone trying to sell something? If you take to the sport, you will end up with multiple suits. A skin suit or 1 to 1.5 mil for warm water, for sunburn and stinging critter protection, a 3 mil for water between 70 and 80, and maybe a 5 or 7 mil if you completely lose your mind and start diving in cold water,or worse, like it. 5 mils are a lot more constrictive to breathe and move, unless you get a freedivers "open cell" suit, which is way more flexible than closed cell, but much easier to tear. Having owned both, I would only use the open cell suit. Get a Yazbeck or one of the other top freediving suits, like Picasso or similar. You will not regret it. For a first suit I would get a 3 mil open cell. You could always double up and put a 1 mil on underneath if 3mil wasn't working for you. 1 mils are the least expensive, and you could buy one in the Keys if you needed to. By end of April water will be in mid 70's at least and 3 mil will be fine. Good luck, have fun, stay safe.