This is from "A Gentleman Gets Dressed Up" which is $14.99 at Jos A. Banks (or just go to the store and look thru the book. It has helped me out immensely. A Washington, DC attorney told me about it a few years ago. And he gets compliments from men and women on how he dresses for any event.
"If the wedding is scheduled in the late morning or afternoon, a gentle is always appropriately dress in a dark business suit or in a dark sports coat, dark slacks, and a tie-the same outfit he would adopt , coincidentally for a funeral. "
It also states, if the wedding is informal (you go by the invitation), then you may dress as he pleases.
"If a gentle a gentleman has any doubts as to what he should wear to a wedding or any other ceremonial occasion, no matter how informal or formal...contact the host or hostess and simply ask, 'What do you think most of the fellows (men) will be wearing?'"
"He does not content himself with with asking uninformed friends"
You look with what have, don't change. unless, it is informal.
Do not follow what Bigbobs, , cause that right there is no home training and a seriously lack of coordinating skills ( do not be a John Witherspoon look alike), nobody wears bright orange shirt and ties, unless they were going thru the Kohls Xmas sales bins. Because in your 20's you can get away with it, but when you dress like that as a habit, and get older, you look like a fool.