Semi-Formal or Dressy Casual Part of dressing for a semiformal or dressy casual wedding is taking the time of the wedding into account. Wear darker, more formal colors for an evening wedding; opt for light colors and fabrics for a daytime event. Try a below-the-knee dress or a dressy skirt and top. An elegant pantsuit is also appropriate. Floor-length gowns, however, would be inappropriate. Pair with heels, nice wedges, or formal flats. Men should wear a dress shirt and slacks, dark or light depending on the time of day, with the option to wear a tie. Semiformal gives you flexibility on comfort, but be sure not to dress too casual.