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Should You Wear Sunscreen In Winter?

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  • Published

    May 18, 2021

  • Written by

    Dr Garth Dicker

At the Collins Cosmetic Clinic we treat many skin problems caused by sun damage. Whilst we can achieve great results in repairing damaged skin we also know that the regular use of Sunscreen is very important in preventing or slowing down further sun damage. In Winter with colder temperatures people are often covered up more under layers of clothing with less skin exposure, however the areas that are exposed still need sun protection. Many patients struggle to believe that daily Sunscreen can still be important during the winter months. The need for Sunscreen in winter is based on understanding that exposure to Ultraviolet radiation can still occur in the colder winter months. Ultraviolet radiation (UV) is not the same as heat. The warmth on our skin that we can feel from sunlight is because of Infrared light whereas we cannot see or feel the Ultraviolet (UV) light which penetrates our skin to cause damage.


Ultraviolet radiation from the sun that can damage our skin is classed as either UV-A or UV-B. The intensity of UV radiation varies by season, location (latitude and altitude) and time of day (most intense between 10am and 4pm in summer). UV-A penetrates deeper than UV-B and contributes to premature skin ageing, wrinkles, and skin cancers. UV-A can penetrate through clouds and glass, such as office and car windows. UV-B damages the upper epidermal skin layer and is the main cause of sunburn and superficial skin damage like redness and pigmentation as well as skin cancer. UV-B can be reflected off surfaces such as water and snow, so as well as direct exposure there can be added reflected UV-B radiation as well. Not all the effects of UV radiation are negative as UV-B is important in producing Vitamin D. This benefit reduces as we get older because ageing skin is not as good at making Vitamin D from UV-B.


In Winter there is a drop in UV radiation and peak UV levels can be around 40% lower than during Summer. Whilst the UV level may be relatively lower in winter it can still be at a dangerous level especially in northern states and at high altitude such as the snow fields. The amount of UV radiation on a particular day is rated on the UV Index and this is available on websites like or apps such as SunSmart. If the daily level is 3 or higher on the UV Index the potential for sun damage is much higher and sun protection becomes more critical irrespective of the time of year.

It is very important to understand that whilst there is a sizeable drop in UV-B in Winter there is a much smaller drop in UV-A. Because UV-A can penetrate through clouds it means UV-A is present with relatively equal intensity throughout the year and that sun protection against UV-A is needed in winter as much as in summer.


Sunscreens are given an SPF rating, which stands for Sun Protection Factor, and the higher the SPF the more protection, with the highest rating in Australia being SPF 50. SPF is determined by a highly regulated clinical test that essentially measures how effective a Sunscreen is at preventing sunburn from UV-B. For example, if skin redness occurs after 10 minutes without sunscreen and 150 minutes with Sunscreen it would be SPF 15 (150/10). A SPF 15 Sunscreen provides 94% protection whereas SPF 50+ provides 98% protection against UV-B. A SPF 15+ sunscreen can provide adequate protection against UV-B but only if it is applied correctly. In testing 2mg/cm of Sunscreen is used (or about 6 teaspoons (30ml) for average adult body) and the Sunscreen needs to be reapplied every 2 hours. However, most people do not apply enough Sunscreen initially and then forget to reapply it correctly, so a higher SPF Sunscreen has the advantage of an added safety margin.

It is important that a Sunscreen also protects against UV-A but there is no internationally agreed standard for testing UV-A protection in Sunscreens. In Australia, a laboratory calculation of protection at 380 nanometers (which is in the UV-A waveband) is used. If a Sunscreen protects against UV-A as well as UV-B, then it is labelled as ‘Broad Spectrum’ and to have this label the UV-A protection of the Sunscreen must be at least 1/3 of the labelled SPF. This means a Sunscreen with a higher SPF will also have higher UV-A protection, so the best Sunscreen is Broad Spectrum SPF 50.


Sunscreens are either Physical blockers (also called Inorganic) or Chemical (also called Organic). The 2 common physical blockers are Zinc Oxide and Titanium Dioxide. Originally these required a thick application of an opaque white layer on the skin but since the 1990’s have been available as microsized or nanoparticles (20-100 nanometers) which are transparent on the skin and much more cosmetically acceptable. Chemical Sunscreens often contain a combination of ingredients to provide coverage against both UV-A and UV-B such as Octocrylene and Bemotrizinol combined with other agents to improve stability.

In Australia Sunscreens are classified as drugs and all active ingredients undergo stringent assessment and most active ingredients in sunscreens have been used for many years and been shown to be safe for long term use in humans. Physical Sunscreens such as Titanium Dioxide and Zinc Oxide have an excellent safety profile. There were concerns at one stage that when formulated as nanoparticles these very small particles could penetrate the skin and enter the body and generate free radicals. This is not considered an issue and these physical Sunscreens are the recommended choice in children as they are not irritating or systemically absorbed. Chemical Sunscreens can have some systemic absorption with regular use and it is best to avoid Sunscreens with Oxybenzone as there were reports of possible hormone effects in animals and it has also been banned in Hawaii since 2018 because of possible damage it can cause to coral reefs.

There are literally hundreds of different brands of Sunscreens and it may take some trial and error to find something that suits regular daily use on your skin. For example, for sensitive skin a hypoallergenic Sunscreen might be needed, for dry skin a sunscreen in a moisturising cream or for oily and acne prone skin an alcohol-based lotion or spray.

It is important to not think of Sunscreen as just protecting from sunburn and only being needed on hot days at the beach or around the pool in summer. Rather think of Sunscreen as protecting your skin from sun damage being caused by UV radiation and that this UV damage can occur all year round. Sun damage is cumulative and not just about full days in the sun but daily moments can also add up to a lifetime of sun damage. At the Collins Cosmetic Clinic our Dermal therapists are very experienced in skin analysis and helping patients work out which Sunscreen might suit their particular skin type and lifestyle. If you have any questions regarding Sunscreens or would like to see one on our Dermal Therapists for a skin consultation, feel free to ring our rooms on 03 96545720 or email us on

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