A common mistake, the hotter it's outside the more we feel the need to shampoo. While everyone likes to have a clean head of hair, shampooing every day can dry out all the natural moisture from your hair, leaving it dry and frizzy. Try shampooing every two or three days and try a milder shampoo, for some dry shampoo can work wonders, a personal favorite is Batiste, you can go up to 3 days not shampooing and maintain your hairs sleek shiny look.
Who doesn't love a blow dry every now and then but having them too often or for too long can end up doing more harm than good. Blow drying your hair leads to drying out the natural oils in the hair causing the strands of hair to actually shrink, so keep drying time to a minimum. Also, try using a cool setting on your hairdryer, it will be less damaging for your locks and it will help get rid of frizzy hair too. The Dyson Supersonic is a great hair drying tool, quick, easy and comes with heat and speed adjustments to suit your hair - a dream for the summer.
The drier your hair, the easier it breaks, the quicker it gets frizzy, so too much brushing (especially harsh and violent brushing) won't make the frizz go away, it will only make it worse. Avoid brushing your hair when it's wet, as your hair is more fragile when it's damp. Also, follow your hair line and brush in the same direction to avoid breakage.
Some hair care products you're using could actually be drying out your hair. Always check product labels and avoid anything that contains isopropyl alcohol or sodium lauryl sulfate. These detergents not only remove moisture from your hair, but they can also irritate your scalp.