Hot weather = even hotter hues.
If you have Meghan Markle Fever (and who doesn't?), Allison Gandolfo of the John Barrett Salon says to ask for a chocolate brown base with highlights around the face but "don't start at the roots." Instead opt for the "grown-out effect, which will require much less upkeep." To keep the color fresh, Gandolfo recommends using the ultra-hydrating hair treatment Olaplex 3.