In most cases, a dark colored suit and tie is acceptable for a male wedding guest, while the groom and members of the wedding party may need to wear a tuxedo. Wedding invitations, or "save the date" notices, often inform guests of the dress code.
Preferred wedding dress varies depending on the season, time of day, setting and preference of the bride and groom. A tuxedo or a suit with a dinner jacket is appropriate, though not typically required, for guests at a night wedding. It is not advisable to wear a tuxedo unless instructed to do so to avoid the risk of wearing clothes that are more formal than those of the members of the wedding party. Bow ties are unnecessary for anyone not wearing a full tuxedo. Tuxedos are uncommon and dinner jackets are inappropriate for guests attending day weddings, especially in the spring and summer months.
According to Business Insider, weddings on a beach or other natural settings are almost always less formal. Beach wedding guests may choose lighter colored slacks, a blazer and a long-sleeved, button-down shirt worn without a tie. No matter what the rest of a man's outfit looks like, single-breasted jackets are a good choice for weddings because they look good on men of all shapes.