Given my epic adventure at Racine (see The Training link), I was extremely concerned about the weather at Louisville. Ironman Louisville was in its sixth year and has had a history of brutally hot temps and is statistically one of the toughest Ironman competitions in the world. All the "easier" Ironman events sell out very quickly, so it's no surprise Louisville is a first-time event for many Ironman competitors.
When I signed up I knew Louisville would be hot and not wetsuit-legal (if water temps are at above 83.8 degrees you cannot wear a wetsuit, which has floatation qualities). I don't love swimming in wetsuits, but I do love that they help you float, so if you panic you have a safety mechanism. This was a big concern to me, even in the week of the race.