January Birthday Personality [Infographics] Are you a January born? Or do you want to know more about someone with a January birthday? Then you have come to the right place! The zodiac signs for the January birthdays are #Capricorn from January 1st to January 19th and #Aquarius sun sign from January 20th to January 31st. The birthday horoscope for each of these days gives an exclusive glimpse into the true nature of a person born on that day.