Why Does Skin Pigmentation Increase In Summer? Hot weather often causes pigmentation, tanning, and patchy skin tone in many people. The primary reason behind increased pigmentation during summer is excessive exposure to harmful sun rays. In hot weather, the body creates extra melanin to defend the skin from UV damage, https://medium.com/@rameshjain5454/why-does-skin-pigmentation-increase-in-summer-599cc6b6d7c5