|Height||138 cm (4'6")|
|Weight||34 kg (75 lbs)|
|Manga||18. Kagerou Daze I|
|Novel||カゲロウデイズ III -the children reason-|
|“||I kind of hate summer.||”|
Hiyori Asahina (朝比奈 日和 Asahina Hiyori) is the deceased friend of Hibiya Amamiya and Konoha and the younger sister of Ayaka Tateyama. She was involved in and died in the groundhog-day loop on August 15th.
- Hiyori is a young girl with black hair, which is tied as two ponytails. Her eyes are brown. She is shown wearing a black top with a pink strapped dress and black shorts. On her feet she is wearing brown sandals with pink straps.
- In Wannyanpu's fanmade PV, she is seen with short black hair and a white shirt with a black strapped dress on top. She also has a bracelet and wears black sandals.
- Ayaka's younger sister, and a little girl who admires the big city. She's incredibly active and also stubborn, and was the person who dragged Hibiya to the city with her. She's popular among her classmates, but not interested in such things, and even Hibiya is only considered a "convenient classmate who listens to what she says."
- Her favorite animal is a cat.
- Her Japanese name origin means "weather".
- Because of the original Kagerou Days video not featuring Hiyori's design; Wannyanpu made her own personal design for her. However, this design was not official, creating confusion from the fans once she was featured in several songs without her fan-made design.
- "My sister ran away from home. She probably didn't even know that I was born. The first time I saw her was when she was in a coffin." To Hibiya in -the children reason-