Makara Sankranti is one of the few Hindu festivals fixed to the solar calendar rather than the Moon, so it falls on roughly the same Gregorian date each year, in mid-January. It marks the moment the Sun enters Makara, the sidereal sign of Capricorn, and begins Uttarayana, the half-year in which it climbs higher in the sky. The day is associated with the end of the coldest weeks, with sesame and jaggery sweets, ritual bathing in rivers, and gifts to those in need. The Aditya Hridayam, the Ramayana hymn to the Sun, is the natural recitation for the day.
Because the festival tracks the Sun's position against the fixed stars, its date is computed from the sidereal zodiac using the Lahiri ayanamsa; the sankranti instant itself can fall on either side of local midnight, which occasionally shifts the observed day.
Regional forms are distinct: Pongal in Tamil Nadu, Lohri on the eve in Punjab, Uttarayan and kite-flying in Gujarat, Bihu in Assam, and Poush Sankranti in Bengal.