We’ve come to the point in the summer where the weather is just about as unpredictable as the outfits in a Katy Perry music video. So instead of battling a curling iron or spending forever on a fancy braid (as cool-looking as they are) tomorrow morning, guarantee a good hair day no matter what with this sleek style spotted on Nicole Richie. Start with a smooth-infusing shampoo and conditioner and towel dry. Drench your hair with an anti-frizz spray that adds gloss as it slicks down, and create a deep side part using the end of a rattail comb. Lastly, brush back hair and into a tight bun to keep the style in place—or, you know, to keep your neck cool all day!. Frizzy hair won’t stand a chance.