Is sunbathing in winter harmful? If you don't protect yourself properly, skin damage, and more, can occur. In the mountains, snow can almost double UV exposure, with consequences that can even include a corneal burn, known as "snow blindness." Cold weather does not protect against sun damage; it often only makes it less perceptible. 

Why sunbathing in winter is harmful even without heat 

Many associate sun risk with summer heat. In reality, skin and eye damage is caused by UV rays, not temperature. 

UV rays are present all year round:

• UVA rays penetrate deeply and contribute to skin aging; 

Both are also present in winter, regardless of the cold. 

Snow can almost double UV exposure 

Fresh snow is composed of billions of ice crystals and air that diffuse and reflect sunlight very effectively.  

According to the World Health Organization, snow and ice can reflect up to 80% of UV rays. This is because the rays do not only come from above (directly from the sun), but also from below (reflected from the snowy surface). 

The result is much more intense exposure than perceived. This is why you need to protect yourself from the sun even in winter, especially in the mountains. 

Altitude further increases the risk 

In addition to snow reflection, there is another factor to consider. UV exposure increases by 4% to 5% for every 1,000 meters of altitude. Skiers, snowboarders, and hikers at high altitudes are therefore exposed to a significant risk of sunburn and long-term skin damage, due to the greater intensity of ultraviolet rays. 

Cold and wind reduce the perception of risk, but not the impact of UV rays.  

The risk to the cornea: what is snow blindness 

One of the most interesting and lesser-known effects concerns the eyes. So-called "snow blindness" is a photokeratitis, meaning a corneal burn caused by excessive exposure to UV rays reflected from snow. 

It can cause: 

It is a temporary damage in most cases, but painful and avoidable with adequate protection. 

Sunbathing in winter is harmful if not done with adequate protection, not only for the skin, but also for the cornea. Snow reflects up to 80% of UV rays, and altitude further increases exposure. Cold is not a shield: it is only an illusion of safety. Protecting skin and eyes in the mountains is essential to prevent immediate and long-term damage. 

Sources

WHO, Skin Cancer Foundation