Master Class: Hot-Weather Hair Tips

"I've prepped Kim Cattrall to film in Morocco and Argentina and also styled models for the Sports Illustrated swimsuit issue," says celebrity hairstylist Ryan Trygstad of NYC's Marie Robinson Salon. "Sizzling temperatures, UV, chlorine, and sweat should never prevent anyone from having a perfect mane during the hottest, most humid months." Here, Trygstad shares his secrets.

As the mercury rises, stock up on shampoos, conditioners, and styling products with UV- and heat-protection. "The sun, arid environments, and salt water dry out ends incredibly fast, so I tell my clients to use an at-home reconstructive mask at least once a week," advises Trygstad. "After you apply the mask, wrap hair with a hot towel to help the ingredients absorb faster. Rinse out your hair when the towel is cool to the touch."

MC TIP: Dyed brunettes and redheads should cleanse weekly with a color-deposit shampoo to prevent fading.

"The more processed your hair is — keratin treatments, highlights, etc. — the more porous and susceptible to damage it becomes," says Trygstad. Since hair can absorb only so much water, dampen strands with drinking water before swimming and comb through a leave-in conditioner. "This will create a barrier against UV and chemicals," he adds.

MC TIP: In a pinch, prevent a sunburned scalp by combing a small palm full of white sunscreen (yellow formulas can tint pale hair) through your strands, starting at the roots.

Trygstad's troubleshooting must-haves: open-ended bobby pins, gloss cream, and body oil spray. "Wet hair is more prone to breakage, and these pins are gentler," explains Trygstad. "Use them to secure updos when you need to hide brassy highlights or want to pull back damp hair for a night out." Use a body oil spray or a light texturizing balm to conceal split ends in tousled waves.

MC TIP: For a perfect, sun-safe beachy look, spritz damp hair with an oil spray containing sunscreen and loosely weave strands into a side braid.

"Always, always, always rinse hair with a clarifying shampoo after swimming to remove color- and texture-altering impurities," notes Trygstad. And don't scrimp on salon visits. "During the summer, you should get trims every month instead of every six weeks to prevent split ends."

MC TIP: Reach for a beer. Rinsing with a pale brew post-swim can help prevent blondes from going green. (The hops neutralize the chlorine.) Just be sure to shampoo after letting the beer sit for a few minutes.