1. Do you seem to spend summer days in and out of the shower? Then switch to a gentle shampoo like Kérastase Bain Après-Soleil ($29), which has ceramide, a lipid that strengthens overly washed hair.
2. While you're at the beach or pool, comb in creamy Warren-Tricomi Protect Organic Hair Shield ($18). Its UV filters block the sun, and after you rinse your hair, natural extracts like sea algae, cactus, nettle, and lavender leave it feeling luxuriously soft.
3. Thick waves look gorgeous tousled; to get the look, use a texturizing product like coconut-scented Fekkai Beach Waves ($20), which is water based and has a fine spray so hair stays light and movable. Spritz onto your damp head, scrunch waves a bit, and don't touch again till hair is dry (the more you touch, the frizzier it will get).
4. To stop hair from expanding in wet weather: Before you blow-dry each section, give it a shot of KMS California Flatout Anti-Humidity Seal ($16). The aerosol mist contains silicone, which blocks moisture from entering the hair, keeping swelling to a minimum.
5. Use Clairol Nice 'N Easy Colorseal Conditioning Gloss ($4.50) once a week to keep color from turning orange or brassy—a year-round problem that gets worse in the summer, when the sun oxidizes pigment.
6. If the season has already left your hair like straw, apply Joico K-Pak Sun Therapy Treatment Masque ($16); the thick formula is packed with antioxidants for damage repair, along with moisturizing keratin.