SPF! Make sure you use a sunscreen with an SPF of at least 15 and that it's broad spectrum, blocking both UVA & UVB rays. Mix a little into your moisturiser at the start of the day. Make sure it's waterproof if you plan to go into the water. Reapply as needed during the day. Keep to the shade during the heat of the day - the sun's rays are possibly the single most important cause of the signs of aging - and drink plenty of water. After a day at the beach or the pool, cleanse with a good shower gel and shampoo and condition your hair, to remove salt and chlorine.
HUMID CLIMATE - Use lighter moisturisers and after shave products, such as gels or lotions, the moisture in the air will make heavier moisturisers feel even heavier on your skin. The propensity in this climate to carry sweat on your skin suggests a focus on cleansing morning and night, particularly if you have oily skin. Keep your underarms and feet deodorised.
DRY CLIMATE - Hot, dry air will sap moisture from your skin, so use richer moisturisers liberally to ensure you maintain the skin's moisture levels, especially on the extremities such as hands, elbows and feet. If you wash your hands regularly, invest in hand lotion or cream. Don't forget your lips, make sure your lip balm has SPF too. Use both facial and body scrubs regularly to exfoliate the skin so that the moisturisers soak in well.