UGG boots are winter wear and usually worn as part of a cold-weather look. They also have a reputation for being casual accessories, so pair them with jeans or a skirt and tights but not with more formal attire.
According to Honey Bear Lane, UGG boots should be worn with close-fitting jeans or tights that can be tucked into the uppers of the boots. This makes the wearer's silhouette look taller and shows off the fur detailing on the boots. The thickness of the UGGs should be balanced out by wearing heavy upper layers such as a puffy coat, sweater or thick scarf.