The answer is yes.
Anytime there is light outside, and the sun is shining, you need to wear sunscreen. The sun has ultraviolet (UV) rays that can damage skin in less than 15 minutes.
What is sunlight?
It is a portion of the electromagnetic radiation given off by the sun. It is composed of infrared (heat), visible, and ultraviolet light.
What are the pros/cons of sunlight?
Pro – sunlight is a requisite for the production of vitamin D in the body.
Con – too much sunlight over many years can lead to risks of skin cancers such as basal cell, squamous cell, melanoma and others.
Which sunscreen to use?
Physical sunscreens such as zinc oxide and titanium dioxide are preferred as they provide instant protection against UV damage by reflecting UV rays. Generally, SPF 30 or more is recommended. Whereas chemical sunscreens, such as oxybenzone or avobenzone, may provide similar UV protection, they require absorption into the skin to absorb UV rays. Thus, you should wait 15-20 minutes after application before venturing outside.
How much to apply?
Most adults need about 1 ounce of sunscreen (about the size of a shot glass) to cover the body. Additionally, it’s important to reapply every 2-3 hours when outside, especially if you are sweating. Skin cancers tend to appear where the sun hits the most, so, for example, the scalp, nose, and ears. So, don’t forget to apply sunscreen to your hair part or inner ears. Wearing a wide-brim hat whenever outside provides extra sun protection you may need in these areas.
But I don’t like to put on lotions…
An alternative is to seek shade, although being under a tree or umbrella only provides you with a sun protective factor (SPF) of about 5, so usually this is not enough. Also, the protection offered may even be lower due to indirect UV radiation, ie. radiation that’s reflected and bounced back from surfaces such as sand, concrete, or grass. Wearing UPF (UV protective factor) clothing is helpful as an alternative to sunscreen. How does this differ from regular clothes? The weave and thread of the fabric has sun protective properties. For example, UPF of 30 means that 1 of 30 units of UV will pass through.
In summary, even on a snowy wintery day or a cloudy rainy day, be safe and wear sun protection. Ideally, it is best to wear sunscreen to areas of exposed skin, UPF clothing, and a wide brim hat.
I am a board certified dermatologist based in Los Angeles. I am a comprehensive dermatologist caring for families. I love seeing children and adults. My youngest patient was 0 days old and her oldest was 110 years old. I have had psoriasis since the age of 8 and considered an expert in psoriasis and psoriasis treatments. I have lectured locally and nationally and published numerous papers on other topics such as skin manifestations of eczema, hidradenitis suppurativa, systemic lupus erythematous, granuloma annulare, microbiome, skin cancers, and more. My expertise includes knowledge in managing complex skin diseases. I am experienced with surgical treatment of skin cancers, as well as non-surgical methods to treat skin cancer and precancerous lesions. I run a full medical, cosmetic, and surgical dermatology practice. I am experienced with the use of complex dermatologic therapy, including biologic therapy, immunosuppressive medications, and phototherapy. I also treats fine lines and wrinkles non-surgically with combinations of botox, fillers, chemical peels, lasers, and radiofrequency. I perform minor surgeries such as excisions for cysts, lipomas, basal cell skin cancer, squamous cell skin cancers, and early stage melanoma. I am physician expert for Kopa for Psoriasis, part of Happify. I have been featured on podcasts and quoted in numerous online and print publications. I am honored to be named “Top Doctor” in Los Angeles magazine. In my free time, I volunteer for community events such as skin cancer screenings and at the local free clinics. I also teach internal medicine and dermatology residents at several academic centers. I try to do yoga every day and every year, I run a half-marathon at the Golden Gate Bridge.