Louisiana Winter Hair Care: Why It Frizzes at 88% Humidity

Key takeaways

• Hammond mornings sit near 88% relative humidity, dropping to the 50s by afternoon. Your hair re-equilibrates twice a day — that swing is the frizz.
• Hard water does not weaken your hair. A controlled study found no significant difference in tensile strength (p=0.858) or elasticity (p=0.874). It's a film and feel problem, not a breakage problem.
• Indoor winter humidity can fall below 20%. Six hours in it raised measured water loss from skin by 26.7%.
• The fix is sealing and moisture, not more washing.

Cami here. Louisiana winter is its own animal. It isn't the dry, static-shock winter that every national hair article is written for. We get damp mornings, warm afternoons, and a heater running over the top of it all — and hair that behaves differently in December than it did in July, just not in the way the magazines predict.

Let me tell you what's actually happening, and what I'd have you change.

Why humid air makes hair frizz

Hair is hygroscopic: it takes up water from the air around it. That isn't a marketing claim — human hair is reliable enough at it that hair was historically used as the sensing element in hygrometers, the instruments that measure humidity.

When hair absorbs water, the keratin structure reorganises and the strand swells. Individual hairs swell unevenly, lift away from their neighbours, and the cuticle roughens. That's frizz. It's a physical response to moisture, not a sign your hair is damaged or that you bought the wrong shampoo.

I want to be careful here. The hydrogen-bonding explanation is sound physics and you'll find it described in Smithsonian among others, but I couldn't find a peer-reviewed source putting a percentage on it. So I'll describe the mechanism and skip the invented statistic.

The number that actually explains your winter

Hammond sits between Baton Rouge and New Orleans. Both average 88% relative humidity at 6am. By 3pm they've fallen to roughly 56% and 61%.

That daily swing of thirty points is the thing no national article accounts for. Your hair absorbs moisture overnight, expands, then gives it back through the afternoon and contracts. Twice a day, every day.

Averages from the World Data Center for Meteorology, via Current Results. Hammond lies between Baton Rouge and New Orleans.

Sources: World Data Center for Meteorology via Current Results; Skin Research and Technology, 2023

A lot of the problem is indoors

This one surprised me. Everyone blames the Louisiana damp — but a lot of the damage is happening indoors, next to your heater.

A 2023 study in Skin Research and Technology held indoor winter humidity below 20% while outdoor air sat around 23%. After just six hours in that environment, participants' forearm water loss rose 26.7% (p<0.01).

"Even individuals with normal skin experience adverse effects when exposed to indoor winter environments for a brief period." — Park et al., Skin Research and Technology, 2023

So your hair goes from 88% humidity outside to under 20% in a heated house, and back out again, and that swing is the stress. It isn't the cold — we barely get cold — it's the swing, and most of it is happening in your living room.

The same study found a 5% ceramide cream raised skin hydration by 73.02%. That is skin rather than hair, but the principle carries: in dry indoor air, the thing that helps is sealing moisture in.

Hard water: the myth I have to correct most

Almost every client who has frizz trouble asks me about hard water, usually having read that it's breaking their hair.

It isn't. A study in the International Journal of Trichology followed 15 volunteers over 30 days, comparing hard water at 212.5 ppm calcium carbonate against distilled water at 10 ppm, then measured the hair.

"The hardness of water does not interfere with the tensile strength and elasticity of hair." — Srinivasan, Srinivas, Mathew & Duraiswami, International Journal of Trichology, 2013

The difference in tensile strength came out at p=0.858. Elasticity, p=0.874. In plain terms: no measurable effect at all.

So hard water is real, but it's a feel and appearance problem. Minerals deposit on the cuticle, hair goes dull and grabby, colour looks flatter than it did leaving my chair — which matters most if you've had lightening or going from blonde to brown done. A clarifying treatment fixes that. A panic about breakage doesn't.

I use Malibu Professional Rehydrate on clients with obvious mineral buildup, usually before a colour service so the colour takes evenly. That's a technique choice, not a research finding.

What I'd actually change this winter

Practical, in order of how much difference it makes:

• Wash less, not more. The AAD's guidance is that dry, textured, curly or thick hair can go as long as two to three weeks between washes. Oily scalps and straight hair may genuinely need daily. There isn't one right answer.
• Detangle wet hair with a wide-tooth comb, not a brush. This is AAD guidance and the single cheapest change on this list. Hair is at its most fragile when wet.
• Seal the ends. A light oil or leave-in on the lengths gives the cuticle something to lie flat against when the humidity climbs overnight. If the ends are already splitting, see how often to actually get a trim.
• Turn the heat down where you can, or run a humidifier in the bedroom. If under-20% indoor air is measurably affecting skin in six hours, your hair is in the same room.
• Clarify monthly if you're on well water or older parish lines. Not because it's breaking your hair, but because the film dulls it.
• Lower your hot tools. The AAD advises limiting blow-drying and using low or medium heat.

"Hair is delicate when it's wet, so use a wide-tooth comb instead of a brush to detangle wet hair." — American Academy of Dermatology, Tips for healthy hair

Common questions

Why is my hair frizzy in winter if Louisiana is humid? Because of the swing, not the level. Hammond mornings run near 88% humidity and afternoons near 56%, while heated indoor air can drop below 20%. Your hair absorbs and releases moisture across those transitions all day, and that repeated swelling is what lifts the cuticle.

Does hard water damage your hair? Not structurally. A controlled study found no significant difference in tensile strength or elasticity between hair treated with hard water and distilled water. Hard water leaves mineral deposits that make hair feel rough and look dull — a clarifying treatment addresses it.

Do I need a shower filter? If your hair feels coated and your colour dulls quickly, a filter or a monthly clarifying treatment can help with the film. Don't buy one expecting it to stop breakage — that isn't what hard water is doing.

If your hair has been fighting you since the heater went on, come see me. I'm at 109 W Minnesota Park Rd, Suite 5 in Hammond, Tuesday through Saturday. Book an appointment and we'll sort out what your hair is actually reacting to.

Cami Gerald is a licensed cosmetologist and the owner of Cosmetology by Cami in Hammond, Louisiana.