Sankranthi means transmigration of the Sun from one Rāshi (constellation of the zodiac in Indian astronomy) to the next. Hence, there are 12 Sankrantis in a year. Each Sankranti is marked as the beginning of a month in the sidereal solar calendars followed in Tamil Nadu, Kerala, Andhra Pradesh, Karnataka, Odisha. On the other hand, in the sidereal solar Bengali calendar and Assamese calendar, a Sankranti is marked as the end of each month and the day following as the beginning of a new month.
 Important Sankrantis
- Makar Sankranti: Marks the transition of the Sun into Makara rashi (Capricorn) on its celestial path. The traditional Indian calendar is based on lunar positions, Sankranti is a solar event. The date of Makar Sankranti remains constant over a long term, 14 January.
- Maha Vishuva Sankranti: Also known as Mesha Sankranti and Pana Sankranti, is celebrated as the Oriya New Year and is marked as the end of a Bengali year. The day marks the beginning of the New Year in the traditional Hindu Solar Calendar. On this day, the sun enters the sidereal Aries, or Mesha rashi. It generally falls on 14/15 April.
In Southern Bhutan and Nepal it is celebrated by eating wild potatoes (tarul)
- "Festivals, Annual Festival - Makar Sankranti (Uttarayan)". swaminarayan.org. 2004. Retrieved 25 December 2012. "Sankranti means the entry of the sun from one zodiac to another."
- "Makar Sankranti". hinduism.co.za. 2010. Retrieved 25 December 2012. "There are 12 signs of the zodiac. There are 12 Sakrantis as well."
- "Festivals of Orissa - Dhanu Sankranti". orissa.oriyaonline.com. Retrieved 24 December 2012. "Dhanu Sankranti is celebrated on the first day of lunar Pousha month."