UV index 4 is the fourth lowest reading on the UV index scale. When the UV index is 4 there is a moderate risk of harm from unprotected Sun exposure. According to the UV index scale, you should stay in the shade when outdoors if the UV index is 4. Wear sun protective clothing, a hat, and sunglasses if you’re going to be in the Sun. Use a sunscreen that is broad-spectrum and SPF-15 or higher on exposed skin, reapply every two hours.
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