Insider: How humidity hijacks your hair

You spend forever doing your hair and then you step outside - and it’s over. It doesn’t even matter if you checked the weather first. Your hair knows, and suddenly you’ve got puff, fuzz, and curls you did not sign up for.

So what’s actually happening here?

It’s all about the cuticle, which is the outer layer of your hair. When it’s lying flat and smooth, your hair looks shiny and stays styled.

But when the air is humid, water molecules sneak in and start lifting the cuticle up—like shingles on a roof peeling open. Once that happens, your strands start absorbing moisture like a sponge, and then you've got frizz.

“The porosity of our hair actually absorbs the moisture and then it causes the frizz, it causes it to pump up,” said Kim Olson, owner of Hair Therapy Salon and Day Spa.

Hair is naturally hygroscopic, meaning it draws in water from the environment. It messes with the internal bonds that hold your hair’s shape - those smooth strands you styled this morning? They’re now reacting to water molecules floating in the air. If your hair’s already dry or damaged, it absorbs even more—and frizz shows up faster and bigger.

The fix? Hydration. “So if we moisturize our hair, then it stops the frizz,” Olson said. When your hair already has the moisture it needs, it’s less likely to grab it from the air.

Also: look for anti-humectant products that block outside moisture. “We want to find products that would be anti-humectant,” Olson added. “And that is going to create more of a barrier.”

Humidity is nature's way of humbling us. But with the right moisture and products, your hair doesn’t have to lose every time the forecast says 70% and climbing.