How can one keep from being sunburned?

Dear Tom,

After watching a ball game, I noticed that my arms had turned pink. I didn’t realize I was going to be sitting in the sun. How can I keep from being sunburned again?

Franciszka,
Chicago

Dear Franciszka,

This time of the year it does not take long to become sunburned. Across the northern hemisphere, sunlight is most intense on the summer solstice, which occurs on or about June 21st. Each day, the sun is strongest at 1 PM (noon if we were on standard time). At 1 PM on a sunny June day, a person can become sunburned in 15 to 20 minutes, about the time it takes to complete an inning of baseball. To avoid sunburn, try to stay in shaded areas during times of peak sunshine. If you think you may be exposed to the sun, apply a water/sweat resistant sunscreen, preferably SPF 50. Dr. Bryan Schultz provides sunburn times that are listed in the digest section of the Tribune weather page.