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.
The problem It's actually an oily scalp that leads to oily hair, says Cheryl Karcher, MD, a New York City dermatologist and consultant for Avon. "Unfortunately, sweating in the heat turns up the oil production even more."
Pro solution: "Resist the urge to shampoo
The problem: Moisture-robbing UV rays can lead to dry, brittle hair, says Michael Dueñas, owner of Hair Room Service in New York City.
Pro solution: Put the sun to work for you, suggests Joel Warren, co-owner of Warren-Tricomi Salons. Before you head outside, take a dollop of conditioner and run it through dry hair. Not only does the conditioner act as a layer of protection from UV rays, but the heat from the sun helps the conditioner to really soften your hair. Swimming is a big cause of dryness, so before taking a dip, presoak your hair in water to help prevent it from absorbing drying chlorine or saltwater.
The problem: The sun can make your hair color go weird, Dueñas saysblame UV rays again. Brunettes take on a brassy tone; blondes get bleached out.
Pro solution: Prevention is the best way to save your color, so don a stylish hat every time you step outside. A good idea: Apply products with built-in sun protection. Keep a UV-protecting spray, such as Phyto Plage Protective Beach Spray ($22; beauty.com), by the doorit will remind you to spritz before you head out. To fix a hue that's already brassy or bleached-out, wash with a color-depositing shampoo once a week; try Ted Gibson Brazen Brown or Glimmering Gold Shampoo ($25 each; tedgibsonbeauty.com). It won't dye your hair, but pigment particles will boost your shade. You can also head to the salon for a gloss (a semipermanent color that's free of ammonia) to eliminate orange or yellow tones.
The problem: Moisture loss from heat styling, the sun, and chlorine may lead to a breakdown of protein in the hair, resulting in breakage, Dueñas says. Constantly wearing your hair up in a ponytail can also be a factor.
Pro solution: Reach for a protein-based deep conditioner to start building up strands. (Limit treatments to once a week, as too much protein can give hair a gummy or elastic texture.) Another tip: Vary the height of your ponytail so you don't overstress hair at the same point; a band that's constantly in one spot can cause breakage. If you have serious splits, there's really only one solution: a cut. "Cropped styles are great for summer," Arrojo says. "Besides, if you're constantly putting your hair up, it may be a sign that a shorter style suits you."