Here is what thickness of wetsuit we wear in various temperatures

Temp	Wetsuit	Chelsea	Wade	Karen
> 82	no suit	8 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.