As spring days get longer and summer approaches, people begin to spend more time outdoors — especially in Colorado, with its 300 days of sunshine per year. 

But sun exposure is the leading cause of melanoma skin cancer, which means you need to be extra careful while you’re soaking up all those rays. University of Colorado Cancer Center member Theresa Pacheco, MD, associate professor of dermatology at the CU School of Medicine, offers these tips for staying safe in the sun: 

Be aware of elevation 

People in Colorado have to be more careful about sun exposure. Denver is at 5,280 feet in elevation, which means it is 5,280 feet closer to the sun than at sea level. For every 1,000 feet you are above sea level, you receive 5% more effect of sun exposure. Do the math, and you see that people in Denver get 25% more effects from sun exposure than people at sea level. 

Limit your time in the sun

We know sunlight boosts the body’s production of vitamin D, and that vitamin D is important for your immune system. But you only need sun exposure for 5 to 30 minutes a day, most days a week, without sunscreen, to boost vitamin D levels. 

Understand SPF 

SPF 30 is the magic number when it comes to sunscreen. It blocks 97% of the sun’s rays. 

Know when to screen 

Get a skin cancer screening every 1–2 years, depending on your risk. Your primary doctor can perform the screening and advise you on your individual risk. 

Know the symptoms 

The top symptoms of skin cancer are a skin lesion that does not go away or a mole that is changing. If you find something suspicious, contact your primary care physician and/or dermatologist. They can view the lesion and decide if a biopsy is needed. 

Reduce your risk 

Protect your skin with sunscreen, hats, clothing, and umbrellas, and by seeking shade. Those at higher risk for cancer from sun exposure include people with red hair and freckling skin, people with multiple moles, people who spend or have spent a lot of time in direct sunlight; and people who use or have used tanning beds. 

This story was published by the University of Colorado Cancer Center on May 1, 2024. It is republished with permission.