Black tie is about as fancy as wedding attire gets (sans the white tie option, which is reserved for the most upscale weddings and dinners like a White House State Dinner). When you receive an invitation with black tie attire requested, it means men are expected to dress in tuxedos with shirt studs, cuff links, and black patent shoes. For ladies, this means formal floor length evening gowns or your dressiest cocktail dresses.
Casual attire usually means that the wedding will be held outdoors. However, this is not a time to break out your flip-flops. It’s also best to avoid jeans, shorts, and t-shirts. For appropriate casual wear think a summer or linen dress that will allow you to stay comfortable all day and night in the summer heat.
If you’re a bride trying to decide which type of attire you’d like your guests to wear to your wedding, it truly depends on the time and venue at which you’re having your wedding reception. If you’re having an outdoor summer wedding, your guests will appreciate casual wear as no one wants to spend an outdoor wedding sweating through formal clothes.
On the other hand, if you’re going for an evening wedding and an impressive venue, by all means you’re allowed to request that your guests wear black tie attire. Evening weddings allow for a more glamorous approach to attire where formal gowns just seem to fit as opposed to daytime weddings.