As widespread heatwaves hit cities across the U.S., the best protection against the sun and UV rays is sunscreen. Every day, about 9,500 people are diagnosed with skin cancer in the United States, ...

You're not alone if you've wound up with a sunburn even though you took time to apply SPF. Experts recommend wearing sunscreen daily, but don't always provide information on how to use it correctly.

I used to think I was pretty good with sunscreen. I followed all the rules: I applied it every morning, no matter the forecast. I kept powder sunscreen in my bag for midday reapplication. I splurged ...