Dakshinayana or Pitrayana is the nighttime of gods in Hinduism and it lasts for six months or till Makar Sankranti. In 2023, Dakshinayana starts on June 21 for calendars followed in North and Western parts of India. For calendars followed in South India, Dakshinayana begins on July 16, 2023. Uttarayana period starts with Makar Sankranti and it is the daytime of Devas. A human year is equal to one day of gods in Hindu religion. Dakshinayana is also the southern transit of Sun and nights are longer during this period.
This is known as Summer solstice in Northern Hemisphere – Summer solstice in northern hemisphere occurs between June
20 and 22. In the Southern Hemisphere, the summer solstice occurs on December 21
or December 22. Summer solstice in northern hemisphere is the longest day.
The summer solstice is the day when the sun travels its
longest path through the sky and reaches its highest point. Due to the
tilt of the Earth on its axis, the North Pole is shifted almost directly toward
the sun, hence summer solstice has the longest day in a year.
In Tamil Nadu, the month Aadi marks the beginning of Dakshinayana. There is also a belief that Lord Vishnu goes to sleep during this period and the Ekadasi just before Karka Sankranti is referred as Devshayani Ekadashi.