Makar Sankranti marks the day the Sun enters Makara, the sidereal sign of Capricorn. It is one of the few Hindu festivals fixed by the Sun rather than the Moon, which is why it falls on the same date in most years, usually 14 January and sometimes 15 January. Families keep it with a bath, charity, sesame and jaggery sweets, and in many regions with kites, bonfires or a harvest meal. It is known by other names too, including Pongal in Tamil Nadu, Uttarayan in Gujarat and Lohri on the evening before in Punjab.
The moment the Sun crosses into Makara is the same instant everywhere on Earth, but the clock time and sometimes the calendar date of that instant depend on where you are. The rule used here is the common one: if the ingress happens before sunset, the festival is kept on that civil day, and if it happens after sunset, it moves to the next day. The auspicious period for the bath and giving is the Punya Kala, which runs from the ingress (or from sunrise, if the ingress came in the night) until sunset. Its first part, the Maha Punya Kala, is considered the best time and is listed separately below.
Why do cities differ? A city far to the east reaches the moment of ingress later in its own evening than a city far to the west, so one place can keep the festival on 14 January while another keeps it on 15 January. Daylight saving changes the clock time but not the day. The times in the tables are worked out for each city from its own sunrise and sunset.
A calm note: Makar Sankranti is a day for gratitude, not for anxiety about exact minutes. If your family or temple keeps a particular day, follow that. The Sun’s sign changes are also listed live on our planetary transits page, and the method behind these dates is described on the method page.