Q&A: Guest Attire: Too Early to Request Black Tie?
Q: Is a 5 p.m. wedding in April too early to ask guests to wear black tie?
A: The old rule: No black tie before 6 p.m. The updated etiquette: If the reception begins after 6, black tie is okay. If your ceremony begins at 5, it's safe to say you're having an evening reception, so it's totally fine. In fact, this rule can be bent for a 4 p.m. start time, if you really want a formal look but can't swing a later start.