Why cooler weather changes your skin—and why your skincare routine might need to change with it.
Every fall, the skincare industry tells us it's time to switch products. Out with the lightweight moisturizers, in with the rich creams. Maybe add a facial oil. Perhaps an entirely new routine.
But here's what I find interesting as a dermatologist: your skin doesn't care what month it is.
It responds to its environment.
And when temperatures drop, humidity changes, and we start turning on the heat, some very real things happen to the skin barrier. Things we can actually measure.
The outermost layer of your skin, the stratum corneum, we often describe as a brick wall. The skin cells are the bricks, and the lipids surrounding them—primarily ceramides, cholesterol, and free fatty acids—are the, you knew it, mortar.
This structure does two incredibly important things: it helps keep water in and potential irritants out.
But the skin barrier isn't static. It's constantly responding to the environment around it.
When the air becomes colder and drier, the water content of the stratum corneum can decrease. Skin may become rougher, less flexible, and more susceptible to irritation.
And here's where things get interesting.
Dry skin isn't just about water.
One of the ways dermatologists study barrier function is by measuring transepidermal water loss, or TEWL.
TEWL measures the movement of water vapor through the skin into the surrounding environment. It's a useful measure of barrier function, although it's also influenced by ambient humidity and temperature.
And the relationship between dry weather and TEWL is more complicated than you might think. More complicated, yes, you are welcome. There is more.
Low humidity doesn't necessarily increase measured TEWL in every experimental setting. But studies consistently show that colder, drier environments can reduce skin hydration and increase susceptibility to irritation.
A 2016 review in the Journal of the European Academy of Dermatology and Venereology examined the effects of temperature and humidity on the skin. The authors found that cold, dry conditions can impair barrier function and increase skin reactivity, particularly in people prone to eczema.
That's not a marketing claim. It's skin physiology.
Your skin may become more reactive to products you've used for years.
In a classic study published in the British Journal of Dermatology, researchers exposed healthy volunteers to common irritants during summer and winter.
They found that skin was significantly more reactive to sodium lauryl sulfate, a detergent commonly used in cleansers, during winter.
The researchers also measured lower epidermal hydration during the colder months.
So try this on for size...
A cleanser you've tolerated perfectly well all summer may suddenly leave your skin feeling tight or irritated. An active ingredient that never bothered you may start stinging.
It doesn't necessarily mean you've developed an allergy to that product.
Your skin may simply be less resilient.
As a dermatologist specializing in contact dermatitis, I think this distinction matters enormously. Irritation and allergy are not the same thing, and a changing environment can influence how well your skin tolerates everyday exposures.
Ok, so we have got all that going and then...We turn up the heat! Literally.
We tend to blame the cold outdoors, but indoor environments matter too.
Heating cold outdoor air without adding moisture can substantially lower indoor relative humidity.
A 2023 study published in Skin Research and Technology evaluated skin changes following six hours of exposure to a heated indoor winter environment.
Researchers documented changes in skin roughness, redness, and other skin parameters, as well as increased TEWL on the forearm.
Just six hours. Count em'. One. Two. Three. Four. Five. SIX!
The study was relatively small, and we shouldn't interpret it as evidence that everyone's barrier becomes damaged after an afternoon indoors. But it illustrates something important: the environment inside our homes can influence skin physiology, too.
So what to do? Change your whole routine?
Maybe. But probably not as dramatically as you've been led to believe.
I don't think everyone needs a completely different collection of products for every season.
What I do think is that your skincare routine should respond to what your skin is telling you.
If your skin starts feeling tight, itchy, rough, or unusually reactive as the weather changes, consider a few simple adjustments.
1. Rethink your cleanser.
Cleansing should remove dirt, sunscreen, and excess oil without unnecessarily disrupting the skin barrier. If your face feels tight immediately afterward, it may be time for something gentler.
2. Increase moisturization before your skin becomes uncomfortable.
Look for formulations that combine humectants (i.e. glycerin, HA), which help attract and retain water, with emollients and occlusives (i.e. squalane, dimethicone, and yes, you know it vaseline) that soften the skin and reduce water loss. Ceramides can also be useful components of barrier-supportive moisturizers.
3. Apply moisturizer when your skin is still slightly damp.
You don't need to wait until your skin feels dry. Applying moisturizer shortly after washing or bathing helps retain some of that water. We mean MINUTES!
4. Consider dialing back irritating actives temporarily.
Retinoids and exfoliating acids can be useful, but if your skin is becoming more reactive, reducing their frequency may help. You don't necessarily need to abandon them altogether.
5. Don't underestimate your indoor environment.
If your home becomes very dry during the colder months, a humidifier may help improve comfort. Keep it clean, and avoid excessive indoor humidity that encourages mold growth.
The part I wish more people understood
Healthy skin isn't simply skin that contains more water.
It's skin that can maintain hydration, tolerate ordinary environmental exposures, and recover from everyday stress.
That's why I'm much more interested in supporting the skin barrier than chasing the latest seasonal skincare trend.
Sometimes that means using a richer moisturizer. Sometimes it means cleansing less aggressively. And sometimes it means doing absolutely nothing differently because your current routine is working beautifully.
The goal isn't to have a winter skincare routine.
The goal is to have skin that functions well, whatever the weather.
And that is a much more interesting conversation than whether it's officially sweater season.
References
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Engebretsen KA, et al. The effect of environmental humidity and temperature on skin barrier function and dermatitis. J Eur Acad Dermatol Venereol. 2016;30(2):223–249. PubMed
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Agner T, Serup J. Seasonal variation of skin resistance to irritants. Br J Dermatol. 1989;121(3):323–328. PubMed
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Park EH, et al. Effects of winter indoor environment on the skin: Unveiling skin condition changes in Korea. Skin Res Technol. 2023;29(6). PubMed
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Engebretsen KA, et al. Ambient humidity and the skin: the impact of air humidity in healthy and diseased states. J Eur Acad Dermatol Venereol. 2016. PubMed
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Löffler H, Happle R. Influence of climatic conditions on the irritant patch test with sodium lauryl sulphate. Acta Derm Venereol. 2003;83(5):338–341. PubMed
