Here is what thickness of wetsuit we wear in various temperatures

Temp WetsuitChelsea Wade Karen
> 82 no suit8 lbs 4-6 lbs 11 lbs
74 to 82 3 mil 11 lbs 7 lbs 14 lbs
72 to 74 5 mil 13 lbs
64 to 72 7 mil 24- 18 lbs 26 lbs
< 62 too frickin' cold

7 mil suits are supposed to be 10% of body weight + 4 lbs.