Do You Need Sunscreen in Winter? What UV Does on Cloudy Days

In summer, sunscreen feels obvious. In winter, when the days are short and grey, it can feel unnecessary. The honest answer is: it depends on where you live, what you are doing, and what your skin is going through.

Two kinds of UV

• UVB causes sunburn and plays a major role in skin cancer. It is strongest in summer and around midday, and much weaker in winter at higher latitudes.
• UVA penetrates deeper into the skin and is a major driver of photoageing — wrinkles, loss of firmness and pigmentation. Its levels vary less through the year than UVB, and it passes through cloud and window glass.²

Clouds, snow and altitude

Thin or broken cloud lets much of the UV through, so a grey day is not the same as a UV-free day. Snow reflects up to around 80% of UV radiation, and UV levels rise with altitude — which is why skiers can burn badly in winter.¹

Winter UV is lower, not absent. On snow and in the mountains, it can be higher than on a summer beach.

Use the UV index

The UV index is a simple guide to how strong the sun is. The World Health Organization recommends sun protection when the UV index is 3 or higher.¹ Many weather apps show it. In northern Europe, the winter UV index is often 1–2, but in southern countries, at altitude or on snow it can be much higher.

When daily winter SPF makes sense

• You are using retinoids, AHAs or other exfoliating acids, which can make skin more sensitive.
• You are treating melasma or dark spots — even small amounts of light can trigger pigmentation. See our melasma guide.
• You spend long periods outdoors, or sit by a bright window.
• You are skiing, hiking or travelling somewhere sunny.

Simple winter routine

A moisturiser or day cream with SPF 30 and broad-spectrum (UVA) protection is enough for most ordinary winter days. For long periods outside, on snow or at altitude, use a dedicated sunscreen, apply enough, and reapply every two hours.³⁴ Read how much sunscreen you really need.

What about vitamin D?

Sunscreen used in normal amounts is unlikely to cause vitamin D deficiency. In many northern countries, winter sun is too weak to make enough vitamin D anyway, which is why some health services advise a supplement in autumn and winter.⁴ See our guide to bone health.