Sun exposure between sunrise and approximately 8 AM, and potentially up to 2 hours before sunset, can help develop a solar callus without burning.

“in Costa Rica I'm so close to the equator this may only be until if I'm going to be in the sun after 8 A.M then I'm going to wear some sunscreen but being in the sun from the sun rises about 5 30 5 30 6 7 8 o'clock maybe even 8 30 without sunscreen could be a good way to develop a solar callus and then being in the sun maybe two hours before the sunset is the other time when there's some ultraviolet radiation depending where you are but not as intense an amount and that's a good way to gradually develop some color in your skin get the solar callus this gradual tan without getting burned”