From Bulbapedia, the community-driven Pokémon encyclopedia.
Horoscope is the popular zodiac of the Unova region that is talked about on the TV show "Personality Assessment and Horoscope", seen in Black, White, Black 2 and White 2 on televisions.
Each of the Pokémon in the zodiac corresponds to a star sign of the real-world zodiac; however, each Pokémon represents a specific month, unlike the real world zodiac, in which one star sign lasts for roughly a month's time but does not correspond to one specific month in the Gregorian calendar. Each Pokémon of the zodiac represents the month that encompasses most of their real counterpart's duration. For example, Pisces represents February 19 to March 20, while Alomomola represents the entire month of March.
The Pokémon zodiac makes an appearance in the TV Show "Personality Assessment and Horoscope". Each episode features one of the Pokémon in the zodiac, and explains their current fortune and also their lucky item. The show is hosted by an unknown person, and information comes directly from a scientist/astrologer by the name of Dr. Astropoff.