Dehydration

As the mercury rises outside, air-conditioning inside becomes cooler, zapping vital moisture and leading to skin dehydration. "Use plenty of cooling and calming masks, boosters, spritzes and moisturisers. Think, 'Let's give my skin a cool drink!'" enthuses Emma Hobson. education manager for The International Derman Institute. "A fantastic ingredient to look for is hyaluronic acid, which holds 1000 times its own weight in moisture and is brilliant for treating dehydration." If you're not spending a lot of time indoors, trade in your super-hydrating winter cream for a lighter gel or fluid formula.

Try: Thalgo Absolute Rehydrating Serum (1), $98; Clinique Moisture Surge Face Spray (2), $45; La Mer The Moisturizing Gel Cream (3), $440.

Sensitivity and hyper-pigmentation

"Increased exposure to UV rays and free radicals may result in skin sensitivity and, for some, hyper-pigmentation," says Hobson. Apply an SPF 30 moisturiser (suitable for your skin type and condition) 20 minutes before sun exposure. "Sunscreens are vital, but need to be cleansed off the skin to avoid build up," she says. "Your routine must be thorough. Try the new pre-cleanse products that are highly effective in removing the skin's oil, dirt, products and debris quickly and easily."

Try: Dermalogica PreCleanse (4), $59; Dr. LeWinn's Facial Moisturising Lotion SPF 30+ (5), $49.95.

Oily skin

"An increase in temperature can stimulate your sebaceous glands to produce more oil," explains Hobson. "Coupled with elevated levels of perspiration, additional breakouts may occur." To tackle this, Hobson advises double-cleansing your skin, combined with the use of an oil-free mattifying moisturiser and a hydrating mist to keep your skin fresh and calm. "Remember your products can be kept in the fridge during the summer for a great complexion cool down," she adds.

Try: Estée Lauder Sparkling Clean Purifying Mud Foam Cleanser (6), $49; Napoleon Perdis Auto Pilot Pore Minimizer and Mattifier (7), $65; Shiseido Pureness Matifying Moisturizer Oil-Free (8), $53.