Is it possible to get a sunburn on a cloudy day?

And yes, you can still get a sunburn on a cloudy day. A high percentage of ultraviolet (UV) light emitted by the sun penetrates through clouds. You still have to try to protect their skin as they would on a sunny day.

Sunburn is caused by excessive exposure to sunlight. This exposure is one of the main causes of skin cancers such as basal cell carcinoma, squamous cell carcinoma and melanoma. The sun emits UV rays, which can penetrate the outer layer of the skin and cause changes resulting in burns. Sunburn can accelerate the rate at which skin ages. There are three types of UV rays: UVA, UVB and UVC. Each has different wavelengths and different consequences for the skin.

Precautions should be taken to avoid sunburn by reducing UV exposure and protecting the skin.

This article looks at whether you can get sunburn on a cloudy day, what the symptoms of sunburn are, and how you can protect yourself from exposure. It also explores the risk factors for sunburn.

Can you get sunburn on a cloudy day?

Even on cloudy days, the sun still emits UV rays, which pass through the clouds and can cause sunburn. Over 90% of UV rays can pass through light cloud cover and cause sunburn. UV levels tend to be highest under cloudless skies, and cloud cover generally reduces a person’s exposure. However, light clouds offer little protection and even increase UV levels due to an effect called scattering.

Many surfaces also reflect UV rays, increasing the overall UV levels a person is exposed to:

– grass, ground or water reflect less than 10% of UV radiation
– sand reflects about 15% of UV rays
– sea foam reflects about 25
– fresh snow nearly doubles a person’s UV exposure.

Types of UV radiation

There are three different types of UV rays, which vary in wavelength. These are the following:

– Ultraviolet A (UVA): This type of light has a wavelength of 315-399 nanometers (nm) and is associated with skin aging.
– Ultraviolet B (UVB): This type of light has a wavelength of 280 to 314 nm and is associated with sunburn.
– Ultraviolet C (UVC): This type of light has a wavelength of 100-279 nm.

UVA rays represent 95% of the UV light that reaches the Earth. UVB is the main type of UV light that causes sunburn. The ozone layer completely absorbs UVC. UVA rays can pass through windows and cloud cover and can cause tanning. There are associations between UVA and skin aging and UVB and skin burns. Both UVA and UVB can damage DNA in skin cells. Prolonged exposure to either of these types of UV rays can lead to skin cancer.

What are the symptoms of sunburn?

Sunburn causes in people of all skin colors:

– a feeling of heat or overheating
– sensitivity to touch
– a pain
– irritation
– itches
– peeling skin
– possibility of blistering

Symptoms usually begin about 4 hours after sun exposure. They tend to get worse within 24-36 hours and usually go away within 3-5 days.
Sunburns are often easier to detect on fair skin, as they can appear red and inflamed. It can be more difficult to spot the redness or subtle pink of sunburn in people of color. As the sunburn heals, the skin may peel in the affected area. It’s important to take care of the skin while it heals, although the sunburn itself should go away on its own within a few days.

Is sunscreen essential?

There are currently two types of sunscreens: physical sunscreens and chemical sunscreens. Physical sunscreens, also called sunscreens, typically contain ingredients such as zinc oxide or titanium dioxide.
Chemical sunscreens contain chemicals that absorb both UVB and UVA rays. They usually include one of the following active ingredients:

– aminobenzoic acid
– avobenzone
– octisalate
– octocrylene
– oxybenzone

Broad-spectrum sunscreens contain blockers that absorb both UVA and UVB rays. Each sunscreen normally displays a sun protection factor (SPF) on its packaging. A higher SPF indicates better protection against sunburn. Sunscreens are essential because they reduce the amount of UV rays that penetrate the skin and lower the risk of developing skin cancer. For everyday use, a broad-spectrum sunscreen with an SPF of 15 or higher should be used. Regular daily use of SPF 15 sunscreen can reduce the risk of squamous cell carcinoma, a type of skin cancer, by about 40%. Similarly, it can reduce the risk of melanoma by 50%. As UV rays can penetrate clouds even on overcast days, it is advisable to wear sunscreen even on overcast days for effective protection.

How to stay protected

There are many ways to protect your skin, reduce your exposure to UV rays and prevent sunburn:

– avoid going outside when UV rays are strongest, for example between 10 a.m. and 4 p.m.
– wear clothes that cover the skin well
– use sunscreen
– wear a hat with a brim
– wear sunglasses that block UV rays
– consider wearing clothing with an ultraviolet protection factor to block the rays.
Choose a broad-spectrum sunscreen that’s water-resistant for 40-80 minutes and has an SPF of 30 or higher.

One should also make sure to apply enough sunscreen to exposed areas of the body. It takes about a full screen shot glass to cover the whole body.
Sunscreen should be applied about 15 minutes before going out, as this is the approximate time it takes for the skin to absorb the sunscreen. However, not all sunscreens are waterproof or sweatproof. Regardless of the SPF, reapply sunscreen every two hours.

One should also make sure to apply the sunscreen to parts of the body that are easily missed, including:

– above the ears
– the back of the neck
– the line of separation of the scalp
– the top of the feet
– behind the knees

Skin changes

Melanin is a pigment found in the skin, hair and eyes. Melanocytes are the cells that produce melanin. When they absorb UV rays, melanocytes increase the production of melanin in an effort to protect the skin from damage. People of color have more melanin-producing cells.
Doctors consider a tan to be evidence of DNA damage. The more the skin is damaged, the more the DNA is at risk of being rewritten incorrectly and giving rise to a precancerous lesion or turning into cancer. Melanin helps block UV rays, but only up to a point. Although the risk of suffering from sunburn is lower in someone with darker skin, they should still use sunscreen and limit their exposure to the sun to reduce their risk of developing skin cancer. .

Sunburn risk factors

Certain risk factors can increase a person’s likelihood of getting a sunburn.

The risk factors that can lead to sunburn are:

– have fair skin
– have light eyes, like blue or green eyes
– have light hair, such as blond, red or light brown hair
– be at high altitude
– take medicines that make the skin more sensitive to light, such as St. John’s wort
– taking medications such as tetracyclines, thiazide diuretics, sulfonamides and fluroquinolones
– taking nonsteroidal anti-inflammatory drugs
– use retinoids
– live in a tropical or subtropical climate.

In summary

Sunburn is caused by prolonged exposure to the sun’s UV rays. UVB and UVA are two types of UV rays that cause skin changes. Doctors generally associate UVB rays with sunburn. UV light can penetrate clouds. This is why you can get a sunburn even on cloudy or overcast days. Symptoms of sunburn are hot or warm skin, itching, pain, occasional blistering, and peeling skin.

You can reduce your risk of sunburn by using sunscreens with an SPF of 30 or higher, wearing appropriate clothing, limiting time in the sun, and avoiding sun exposure when light UV is the strongest, ie between 10 a.m. and 4 p.m. Some people have a higher risk of sunburn, such as fair-skinned people, those taking certain medications, and those who work or spend a lot of time outdoors.

Protective measures, such as frequent application of sunscreen, regardless of skin color, should be taken to reduce the risk of developing skin cancer.


Gabros, S., et al. (2021). Sunscreens and photoprotection.

Guerra, K., et al. (2021). Skin cancer prevention.

Radiation: Ultraviolet (UV) radiation. (2016).

* Presse Santé strives to transmit health knowledge in a language accessible to all. In NO CASE, the information given can not replace the advice of a health professional.

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