The hottest months of the year are a time when you must revise the content of your makeup bag.
The changing weather calls for new moisturizer and foundation formulas. You may want to switch to non-greasy products as hot weather stimulates oil glands. If your skin is mixed or oily, find a full cosmetics line that will purify, moisturize and mat your skin. That includes cleansing products and liquid or compact foundation.
You might also want to use facial scrubs and peel-off masques more often. Do not forget to apply a moisturizing cream afterwards.
It also may be worth considering a new makeup palette to harmonize your tanning skin and summer wardrobe. For days when you plan to stay out and involve with a lot of physical activities - like swimming - get a waterproof mascara. Try powder eyeshadow and blush if you usually wear creamy formulas. That will help you avoid clogged pores and smudging.