How long before sun exposure should sunscreen be applied?

Applying sunscreen 15 to 30 minutes before sun exposure is essential for ensuring maximum effectiveness. This timeframe allows the sunscreen to adequately bind to the skin and form a protective barrier against harmful UV rays. Sunscreen needs time to absorb into the skin to provide even coverage and optimal protection.

If sunscreen is applied too close to sun exposure, it may not have sufficient time to take effect, potentially leading to skin damage. It is also important to apply a generous amount of sunscreen to all exposed skin and to reapply it regularly, especially after swimming, sweating, or towel-drying.

The other timeframes offered do not align with the recommended guidelines, as applying sunscreen too soon or too late may compromise its protective capabilities. Thus, the correct answer emphasizes the need for the recommended 15 to 30 minutes pre-application to enhance skin protection.