What to wear for 49-55 degrees

Did one a few weeks ago that was 45 and cloudy. How long are you expecting and how hard are you expecting to go? I have a little more size than an elite, but still rather trim compared to an average person, also tend to be up front. I also tend to do well with colder weather.

Taped the bike shoe vents, used a heavier than normal pair of socks. That's it. There was a 2 mile hill about 5 minutes in, so was well warmed up rather quick. Only other thought was some small gloves, but decided not to. I used a full-sleeve wetsuit for the swim, but it was more to keep warm before getting in the water. Figure out some other method if that isn't an option. Your body can put out substantial heat once you get going hard.

It depends in part on how fast you are and your sensitivity to cold.  For me personally, I race sprints at the temperature in just tri top and tri shorts or tri suit.  For someone smaller and slower who is more prone to being cold, I normally recommend throwing on a snug fitting long sleeve top in T1.

Had a sprint duathlon this morning that probably showed these differences well. Temps were ~37-41F through the event. A lot of people probably rightfully wore a tight long sleeve shirt to handle the bike. Some slightly more. I only went for arm sleeves on the run (to save transition time) and added full finger gloves for the bike. Worked perfectly. I did end up as one of the front few in the (small) race, and of the ones up there it did look like I was the biggest by both height & weight, so it's very likely I was putting out the most power and therefore the most heat. I didn't need as much as the others to stay warm. Also wasn't out on the course as long.