UV rays are the primary cause of visible signs of skin aging: dark spots, loss of firmness, and uneven skin tone. Without adequate sun protection, these effects build up gradually, even on cloudy days.
A clinical study involving 298 women, published in *Clinical, Cosmetic and Investigational Dermatology*, found that sun exposure is responsible for 80% of visible signs of facial aging —including wrinkles, age spots, and loss of firmness.
According to the American Academy of Dermatology, up to 80% of UV rays reach the skin even on cloudy days—which is why it’s important to wear appropriate sun protection year-round, not just in the summer. It also acts as a shield against sunburn and the discomfort associated with prolonged exposure, two factors that weaken the skin barrier over time.