Hair Science Rant: Utah Winter Curl Damage Explained

Everyone blames snow and cold for winter hair damage, but the real enemy is humidity instability. Utah usually swings between snow/no snow, which means constant cuticle expansion and contraction. This year has been drier and more stable and ironically, my hair is calmer for it.

Hair is hygroscopic. It absorbs and releases water from the environment. When humidity spikes, the cortex swells; when it drops, it contracts. Repeated swelling + contraction = cuticle fatigue, micro-cracks, and eventually breakage. Less fluctuation = less stress.

Enter the true villain: indoor forced-air heat. Furnaces and car heaters tank relative humidity (often into the teens), even if your thermostat is a cozy 71°. Low humidity creates a moisture gradient that literally pulls water out of the hair shaft not just surface dryness, but internal dehydration.

This is why I’m still steaming my hair and using a leave-in conditioner a few times a week. Steam temporarily raises localized humidity, softens the cuticle, and allows conditioning agents to penetrate more effectively. The leave-in then acts as both a humectant and an occlusive to slow moisture loss afterward. My go to is Davines Oi All in One Milk 

Winter pro tip: humectants alone (hello glycerin) can backfire in low-humidity environments. If the air is drier than your hair, they’ll pull moisture out instead of in unless they’re buffered with emollients and occlusives.

Porosity matters. Higher-porosity hair loses water faster ( hello highlighted queens) and benefits most from layered hydration strategies; lower-porosity hair needs heat or steam to even get products past the cuticle in the first place.

Soooo with this said: winter hair health is less about temperature and more about dew point, relative humidity, porosity, and how often your cuticle is forced to open and close. Control the environment → protect the cuticle → keep the cortex hydrated → better hair days.