Humidity — Why Our Hair Needs Water
And why frizz might be your hair’s way of asking for help
When I was little, I thought humidity was just what happened when the air got sticky and Mum’s fringe went rogue. Now I know—it’s your hair's way of reacting to the water in the air. And after years working backstage at Fashion Week in Paris, Milan, London, and New York—where models rush from rainy streets to hot lights to air-conditioned tents—I’ve seen firsthand: humidity doesn’t ruin your hair—it reveals what it’s missing.
With summer creeping in and the air getting heavier, I thought it was time we talked about what humidity really is—and why your hair actually needs it.
What Is Humidity, Really?
Humidity = water vapor in the air. On hot, muggy days, the air holds more of it. And because hair is hygroscopic (aka it naturally absorbs moisture from the environment), it reacts. When your hair’s dry or damaged, the outer cuticle opens up like roof tiles in a storm—and things get... chaotic. Think halo frizz, undefined curls, flat roots, or that confusing mix of greasy scalp and crispy ends.
But here’s the thing: that reaction? It’s your hair trying to hydrate itself. It’s reaching out for water wherever it can get it. So if frizz or puffiness is your summer default, it might actually be your hair telling you it’s thirsty—not misbehaving.
Hydration Starts at the Scalp
I’ll say it louder for the people in the back: your scalp is your foundation. It sets the tone for how your hair grows and behaves. If your scalp is balanced and hydrated, the hair that grows from it has a tighter, more compact cuticle structure. That means fewer openings for moisture to rush in and cause frizz.
But if your scalp is out of whack—maybe from build-up, hard water, silicones, or artificial fragrance-filled products—the environment for growth is compromised. You end up with hair that’s more porous, more vulnerable, and more likely to freak out when the air gets humid.
So let’s break it down:
Unbalanced scalp = porous hair = frizz magnet
Hydrated scalp = strong foundation = chill, glossy hair
How to Actually Hydrate: From Root to Tip
Think of it like skincare: hydration works best when it starts at the source. After washing your hair (ideally with a gentle, pH-balanced shampoo), apply a scalp serum while your scalp is still slightly damp. The moisture helps actives like hyaluronic acid, bamboo extract, or aloe vera penetrate deeper and bind water to the skin—just like your facial serum does for your cheeks.
This gives your follicles what they need to produce smoother, stronger strands. It’s a long game, but trust me—scalp-first hydration transforms how your hair handles humidity.
Then move on to your ends. They’re the oldest and driest part of your hair, and they’ll always be first to react to changes in the air. After gently towel-drying (no aggressive scrubbing, please), apply a light leave-in conditioner through mid-lengths to ends. This helps seal the cuticle, reduce puffiness, and block excess moisture from crashing the party.
Bonus: It makes your hair way easier to manage, whether you’re air-drying in the sun or blasting it with a round brush.
TL;DR
Humidity isn’t the enemy—it’s feedback. If your hair’s hydrated and happy, it doesn’t overreact when the air gets thick. But if it’s dry, porous, or depleted, it’ll tell you. Loudly.
So instead of trying to fight frizz this summer, listen to it. Your hair might just be asking for what it really needs: water, nutrients, and a little scalp-first TLC.
My Shower Thoughts
Since we’re already talking about humidity and hydration, let’s zoom out for a second—because frizz might be loud, but thirst is louder. Hydration doesn’t stop at your scalp. Colm and I are unashamedly electrolyte people, and we’ve tried just about every powder and packet out there. So here’s our very unofficial, very honest roundup of what’s worth sipping—especially when the air feels like soup and your hair isn’t the only thing wilting.
LMNT – The OG. It’s salty (like, really salty), but I weirdly love it. I go for the Grapefruit or Orange when I need a serious recharge.
Nectar – Colm’s favorite. Tastes clean, has no weird aftertaste, and doesn’t make you feel like you just licked a pretzel.
Salud Hydration – Our house favorite. Every flavor slaps, but the Horchata and Guava are next-level. Bonus: they make you feel like you're on holiday.
DripDrop – Haven’t tried it yet, but my team swears by the sugar-free Lemon. Apparently, it tastes like the lemonade you'd buy from a 7-year-old on a cul-de-sac—and that’s the vibe we all need sometimes.
Until next wash,
Helen