In my experience, the standard response to this question is:

“It’s winter – why do I need to wear sunscreen?”
“It’s cloudy and overcast, so no.” 
“I have no plans to go out today.”
Or my favourite: “Sunscreen is for Caucasians, and I am much darker, so why should I wear sun cream?”

Almost all skincare experts agree that if you live in a place like Dubai, you should wear sunscreen 365 days a year, especially if you are Caucasian (and even if you are not). But let’s delve further into the why.

What Is the Difference Between Solar Radiation and UV Radiation?

Solar radiation – or the sun’s rays – includes ultraviolet radiation (UV), infraredradiation (IR), and visible radiation (which enables us to see). In this article, we are only interested in UV radiation which, for our purposes, comprises of UVB radiation and UVA radiation.

UVB radiation is the shorter, more energetic radiation and about 5-10% of total UVR. The inflammation of the skin (sub burn) and the resulting reddening of the skin (erythema) are mainly caused by UVB radiation. UVA radiation has a longer wavelength and less energetic radiation, and forms about 90-95% of total UV radiation. Therefore, the bulk of UV radiation reaching us is, in fact, UVA.

UVA, because of its longer wavelength radiation, penetrates our skin deeper and is responsible for photoageing (premature ageing of skin caused by sun exposure). UVA radiation is a longer wavelength radiation and penetrates our skin deeper, which causes the breakdown of collagen (what gives our skin its structure and resilience) in our dermis (second layer of the skin).  

This can lead to premature ageing characterised by hyperpigmentation, wrinkles, loss of skin elasticity, and so on. Tanning is also mainly caused by UVA. Both UVA and UVB negatively impact the body’s immune system. It’s also possible for the skin on your eyes to burn, causing inflammation andcataracts (the latter in the long run), which is a major source of blindness globally. Most notably, both UVA and UVB have been implicated in skin cancer (UVR, including UVA and UVB, is a recognised carcinogen).

Sun Damage Can Be Worse than You Think

No amount of serum or anti-ageing product changes the fact that sun damage is cumulative. That means your skin does not ‘forget’ the number of times you forget to apply sunscreen. If it did, then we would not age. In fact, the main cause of extrinsic ageing (which is ageing caused by diet, lifestyle choices, and the environment) is exposure to UV radiation.

Some estimates attribute visible ageing by UV radiation to as much as 90%. Unfortunately, by the time we are adults, we will have experienced the bulk of sun exposure. Based on a 78-year lifespan, the Skin Cancer Foundation estimates that by the time we are 18, we will have experienced 23% of sun exposure – and this rapidly increases to close to 50% by the age of 40.

Where Does Sunscreen Fit In?

Sunscreen products can be effective in preventing sunburn. Scientific findings also suggest that they can prevent the damage linked to photoageing and protect against induced photo-immunosuppression (suppression of adaptive immune responses caused by exposure to ultraviolet radiation). Therefore, it’s really important that sunscreens contain filters that protect against both UVB and UVA radiation.

Why Should You Wear Sunscreen Every Single Day?

The temperature in our environment changes by season. In Dubai, the temperature can even go well below 10ºC in the winter. But temperature is not related to UV radiation. The factors that affect UV radiation (and therefore photo-damage) are geography, altitude, time of year, day and weather conditions, and reflection.

Weather conditions refer to cloud cover – while it may be hazy due to sandstorms during the summer months in Dubai, that’s certainly not the case in winter. The skies are clear, and that means there are no blockers for UV radiation. Similarly, surfaces such as snow, sand, water, and grass reflect UVR, which can hit us if we are not wearing adequate sun protection. If you like to go trekking during the winter, keep in mind that the higher the altitude, the greater the UVR exposure as the atmosphere is much thinner there.

Do I Need to Wear Sunscreen If I’m Not Caucasian?

There is no such thing as totally UV-resistant human skin. All people of all skin tones stand to benefit from sunscreen. As an Indian who’s concerned with the vanity aspect of sunscreen and how it delays photoageing– which not only includes wrinkles and fine lines, but also uneven skin tone and pigmentation – sunscreen is a really cheap and effective method to preserve the existing health and age of your skin. So, using it even if you are Asian might be the smartest skin investment that you make.

But Does It Matter If You Spend All Your Time Indoors?

Remember that UVA radiation is the enemy here and, unlike UVB (which cannot penetrate glass), UVA (which causes premature ageing) can penetrate glass – irrespective of whether it’s a car, a train, or an office window.