In NYC, only nudity is prohibited. As you can imagine, the range of dress varies.
I would offer that, because a jury is charged with a solemn duty, even in the context of civil litigation, but will be sitting in one location for long periods of time with unpredictable climate control, one ought to dress a) as if a attending an official funtion (business casual at worse) and b) in the more comfortable version of those clothes. I would wear treousers, sportscoat, shirt, tie, and comfortable shoes. If in a summer environment, be prepared for possibility that courthouse A/C may not be very good. Take lots of reading material.