The Best Wedding-Guest Dresses to Wear This Spring and Summer

A white-tie dress code is the most formal of them all, dictating floor-sweeping evening gowns. Essentially ask yourself, would this dress work next to a tuxedo? To be safe, opt for a long gown with lots of volume or movement in the skirt so you don't risk flashing a little leg or ankle. This Cult Gaia Iris Gown ($1,398) is elegant and sultry (hello, hip cut-outs) with a unique ombré effect.