Due to the overwhelming success of I Hear the Sunspot, the sequel has finally arrived, I Hear the Sunspot: Theory of Happiness! How will this "more than friends, less than lovers" relationship evolve? (Source: One Peace Books)

Hidamari ga Kikoeru: Koufukuron was published in English as I Hear the Sunspot: Theory of Happiness by One Peace Books on February 13, 2018. It was also released in Polish by Dango on May 20, 2017.