We all love the feel of warm sunshine on our skin! But sun exposure is considered the primary trigger for developing melasma. Photo-damage from UVA and UVB rays exposes skin to harmful free radicals that can trigger hyperpigmentation. Melasma can occur year-round, although increased hyperpigmentation and melasma typically develop or become more noticeable in the sunny summer months. Your best bet is to reach for that SPF every time you leave the house.