On the hierarchy of undesirable weather, humidity ranks at the top — yes, even above rain. At least with rain, you know it's coming: You'll put on the rain jacket, bring the umbrella, plan to wear your hair up (and, more importantly, not waste your time blow-drying it that morning). But humidity is the silent killer. It sneaks up on you, and you don't know how bad it really is until you happen to catch your reflection in a pane of glass and find a full-on unexpected frizz fest staring back at you.
Humidity hits our hair so hard because of hair's porous nature, which absorbs all the moisture in the air. When hair is color-treated or especially dry, it's even more susceptible to puffing up. The key to fighting frizz in the summer isn't necessarily an in-salon keratin treatment or semi-permanently adopting the 24/7 ponytail lifestyle; it's actually as easy as finding a smoothing product that works — and it doesn't have to cost an arm and a leg, either.