I did the half triathlon last year and the weather was pretty crappy (cold and rainy). I think the water temp was low 60's (maybe high 50's?) I can't remember the exact temp but it was cold. I use a sleeveless wet suit and remember my arms getting numb until I really started to warm up about 15 minutes into the swim. I did a pretty good warm up but ending up standing around for 15 minutes and got cold, so that didn't help. As for the run and the ride, they were both hilly, nothing crazy but I thought it was a tough course, especially the bike (two laps for both the bike and the run). I am not sure if the course is the same lap or different for the Olympic. I hope that helps and good luck.