Sun protection, including the use of sunscreen, is generally recommended when the UV index reaches 3 or above. At this level, the sun's ultraviolet rays are strong enough to potentially damage the skin and increase the risk of skin cancer, so applying broad-spectrum sunscreen with at least SPF 15 or 30, wearing protective clothing, hats, and sunglasses is advised

. Here's a summary of UV index levels and sunscreen recommendations:

• UV Index 1-2 (Low): Minimal or no sunscreen needed for most people. You can safely stay outside with little protection, though daily sunscreen is still beneficial for sensitive skin or prolonged exposure

• UV Index 3-7 (Moderate to High): Sunscreen with SPF 15 or higher is recommended, along with other protective measures like seeking shade and wearing hats and sunglasses

• UV Index 8 and above (Very High to Extreme): Extra protection is needed, including high SPF sunscreen, protective clothing, and limiting time outdoors during peak sun hours

Some sources suggest applying sunscreen starting at UV index 3, while others recommend more caution beginning at UV index 5. However, the consensus is that sunscreen becomes necessary at UV index 3 or higher to reduce skin damage risk