It's September in Maryland, where over the past few years it's much more likely to be on the warm end than on the cool end. Last year was in the 80s by midday.
- Swim: been doing races out there for a decade, and last year was the first time I'd seen the Choptank River really live up to its name. Swims are swims. You can either go one way or the other. It was fairly choppy, pretty warm (wetsuit legal, though), very salty and that time of year there's always a good chance of stinging sea nettles.
- Bike: think of the most boring ride you could possibly do. Then double it. The only elevation changes are the couple of tiny bridges you go over. Last year was pretty windy. I just raced out there this weekend and even when it's not terribly windy, it feels windy.
- Run: last year's run course was a triple out-and-back on this unshaded road. Each time you came back you did a lap around the track. I've heard they changed it now so that transition is all within Great Marsh Park (like Eagleman) and the run is going to be a couple of out-and-back, out-and-back through the neighborhood and then into "downtown" Cambridge. This will make it much better for spectators and probably a little more palatable because at least you can't see where you're going for a few miles.
When it was Chesapeakeman, maybe 150 people did the iron distance. I've heard there are something like 1700 signed up right now for this year. Put that IM on it, lipstick on a pig. Good luck though, hope you enjoy it! Be sure to check out the town of Easton, which is pretty nice and just about 15 minutes from Cambridge. October 3rd date for the future is probably to mitigate the chances of it being in the 80s and help get the water temp down a little.