Separates are definitely appropriate for wedding guest attire. Weddings are to dress up for and celebrate a joyous occasion. Separates in dressy fabrics or styles are very stylish and dressy. If you are short or have a few extra pounds choose a monochomatic color scheme (one color or shades of the same color) for your outfit. Pants or skirts in silk, satin, velvet, metallic or sparkles with a flattering top would be awesome to wear at a wedding. If you are tall or skinny separates in different colors can be very flattering. Keep in mind the time of the wedding. You can go a little more glitzy at evening weddings. Any colors but white are acceptable at weddings.
Be a stylish wedding guest! Weddings are to celebrate, occasions to dress up. The wedding invitation provides the information to help you decide what to wear. Daytime (morning and afternoon) weddings are more casual than evening or formal weddings. Today any color is appropriate with the exception of white which is reserved for the bride.
Wedding guests want to look stylish and be in good taste. Knowing what type of wedding you will be attending is the first step. Is it a casual backyard wedding? A beach wedding? A barn wedding? A formal wedding? or a semi-formal wedding?