I got my confirmation email for the Lake Mills Triathlon this Sunday. Here is the part talking about the swim leg:

Swim: The 1/4 mile swim is a counter-clockwise rectangular swim with the buoys on your left. We will have lifeguards on the swim course. The temperature of Rock Lake as of today is 58 degrees. The swim will NOT be canceled. You are permitted to wear wetsuits. Sorry, but I don't know where you can rent them, if you don't have one. Swim caps are mandatory, and I have a few extras if you foget to bring yours.

Time to get my wetsuit out and try it on again for this year. If I'm not fully awake at the start of the race, I will be about 2 seconds after getting in the water.