The bay is much calmer, which should make for a great swim. In addition, they moved the race up 2 weeks, which may also mean better weather. I raced this one 3 or 4 years ago and the lake water was smooth like glass. The last few times, the waves were seriously choppy and the swim was tough -- and I've swum Alcatraz.
I've swam across the bay twice, once in a light rain, and had no wave issues. Except for the shipping channel out in the middle, it's only 12-15 feet deep, and as you first stride in, you'll feel the seeweed up to your thighs. The water is relatively clear -- you can see your extended hand and the feet of the guy in front of you, but you won't see the bottom.
A wetsuit would be good for bouyancy, but probably not necessary for temp. I'm guessing the bay water should be in the low 70s by now.
This is a well-organized race and one of my favorites. The bike is enclosed within the peninsula, and car traffic is restricted to 25mph.
(And the speed limit is vigorously enforced!
) The run has a stretch in the second 1/2 along the sand, which will surprise your legs. I've met folks from all across the state who make this race part of a beach weekend getaway. The race usually sells out, and you'll see a line of 'stand-bys' at the registration table. If you don't pick up your chip by a certain time, the race director releases it.
Have a great race. Right now, it looks like I'm going to miss it, but if my plans change, I'll be riding a burnt-orange Felt, so say hi.