To keep save the skin from sunburn, sunscreen is best to all, use any best SPF30 before going outside. If the weather is cloudy then also use SPF it protects your skin. If you have sunburn then you can use Aloe Vera its has the best properties to fight agains sunburn...
Kind of sunscreen you use may vary depending on the type of outdoor exposure you are expecting. For incidental sun exposure — when you are outside only for minutes at a time — a sun protection factor (SPF) of 15. Your sunscreen should have broad spectrum protection, meaning it effectively protects against significant portions of both the ultraviolet A (UVA) and ultraviolet B (UVB) ranges of the light spectrum. Most broad-spectrum formulas contain multiple sunscreen ingredients. For extended, intense exposure, you should use a broadspectrum, water-resistant sunscreen with an SPF of 30 or higher. SPF 30 filters out up to 97 percent of the sun’s UV radiation; SPF 50 filters out up to 98 percent.