The Royal Style Rule About Wearing Hats That Kate Middleton Nearly Always Follows

For members of the British royal family, there are many (incredibly strict) style and etiquette rules to follow. Certain colors are off-limits, modesty is always a must, and even something as minor as nail polish is strictly regulated. As far as royal fashion rebels go, Kate Middleton does not typically find herself among that cohort. Like wearing black solely during mourning periods, which is one royally strict fashion rule Kate Middleton rarely breaks, the Princess of Wales doesn't depart from this style code often: only wearing hats during the day. 

Royal fashion tradition dictates that hats should be worn between 6 a.m. and 6 p.m. — never in the evenings. As Grant Harrold, the former royal butler to then-Prince Charles, explained to Hello! in 2025, royal ladies who are married will typically swap their hat out for a tiara during evening events. Per the rule, unmarried women will not wear tiaras for late engagements, signifying that they are open to a relationship. As the Princess of Wales, Kate has followed this rule diligently since her formal entry into the royal family in 2011 (with the rare lapse on occasion).  

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For the second day of Royal Ascot in 2026, Kate made her return to the annual horse racing event after a three-year hiatus in epic fashion (literally). The royal style icon complemented her sunny yellow dress in an elegant disc-shaped hat complete with yellow netting. For a daytime event like Royal Ascot, her hat was as appropriate as it was fashionable. In comparison, for the South African state banquet in November 2022, which was an evening affair, Kate opted for a glittering tiara — the correct choice for a married royal after 6 p.m. Unlike the celebrities who ignored fashion rules when meeting royalty, Kate almost always follows the hat-tiara rule to a T.

While some members of the British royal family are more modern in their interpretation of regal style conventions — like Meghan Markle, who has proven she's free from royal style rules on numerous occasions — others, like Kate Middleton, prefer to err on the side of caution when it comes to their wardrobe. Kate Middleton gave an iconic '80s Princess Diana look a chic update at Trooping the Colour 2026, pairing a pale-blue suit dress with a wide-brimmed hat to match, which was the perfect option for a public-facing morning event. For a state banquet in honor of the German president and first lady in December 2025, Kate donned an elaborate tiara. As a married royal woman attending an evening event, her tiara was in alignment with the family's etiquette rules.

The Princess of Wales often follows the many other unwritten royal style rules during public appearances. One such rule encourages women to wear bright colors rather than neutral or moody shades. Typically, Kate follows in the footsteps of her late grandmother-in-law Queen Elizabeth II by donning bold blue, red, and yellow during afternoon events (though she has been known to bend this rule from time to time). Additionally, Kate has been pictured with brightly colored nails rather than the preferred neutral (something that her daughter Princess Charlotte channeled for Wimbledon 2025, as she broke royal style tradition with her bubblegum-pink manicure). While none of these fashion rules are set in stone, they are highly encouraged for royal women like Kate to follow in their daily lives, and the future queen is definitely toeing the line.