Are you a wedding vendor? There's no official uniform for that title, other than "wear dark clothing". Really descriptive, right? As a wedding photographer in Virginia, I always struggle to find an outfit that isn't as boring as a black shirt and black slacks.
But also, if you are a wedding vendor, comfort is usually your top priority because those days are LONG. You're on your feet for 10-12 hours or more. I always need the whole next day just to recover from the activity my body experiences during a wedding day. It's wild. Did I just run a marathon? My body is wondering. Nope, just photographed a wedding, though. If you aren't a wedding vendor, chances are, you don't understand the day after a wedding feeling. It's real.
It's true, you probably should wear dark colors. Why? Because you don't want to be a distraction during important moments. You're moving around during the ceremony. The last thing you want is to take attention away from the couple.