The best way to beat the sweltering humidity: Trim your locks, says David Evangelista, a celebrity stylist at Cornelia Day Resort in New York City. Moisture in the air soaks into damaged areas, causing the hair shaft to swell. Snip off split ends and hair instantly looks healthier and is less prone to frizzing, he explains. To prevent fraying, use products that contain proteins to strengthen strands, such as John Frieda Frizz-Ease Daily Nourishment Leave-In Fortifying Spray, $5.99, drugstores, and Herbal Essences Long Term Relationship Leave-In Split End Protector for Long Hair, $2.99, drugstores. Thinking about a short cut? A chic, off-the-neck bob is a great contrast to flowy summer fashions -- but skip this shape if you have extremely coarse or curly hair, says Evangelista.