Why Is Skin Pigmentation More Common In Hot Weather? Hot weather often causes pigmentation, tanning, and patchy skin tone in many people. If you are wondering, Why Does Skin Pigmentation Increase in Summer?, the main reason is increased exposure to harmful UV rays from the sun. The skin increases melanin https://sites.google.com/view/drnikita-patel/blog/why-does-skin-pigmentation-increase-in-summer