The problem: Your locks naturally crave moisture, so when it's humid out, hair feels the dampness in the air and sucks it upespecially curly and dry types, says Nick Arrojo, owner of Arrojo Studio in New York City. Result: crazy frizz!
Pro solution: The first way to fight frizz is by switching to a hydrating shampoo and conditioner. When you give hair what it wants (moisture, in this case), it will be less likely to grab it from the atmosphere, explains Mustafa Corumlu, a hairstylist at Salon Jean-Paul in Washington, D.C. Next, stop fighting your natural texture. "Manipulating your hair with heat appliances causes damage and creates frizz," Arrojo says. Instead, apply a dime-size amount of an anti-humectant styling lotion, like Frederic Fekkai Advanced Brilliant Glossing Cream ($24 for 4 ounces; fekkai.com), through towel-dried hair to seal moisture in and humidity out. Just rub it between your hands, then run it through your hair as if you were pulling it back into a ponytail.