This festival is celebrated for the birth of the Tamil month of aadi. It is believed that the ’Surya Bhagawan’(the Sun God), changes the direction of his chariot from north to south, so this changeover is celebrated as a festival. This falls sometime between July 15th and August 15th, the beginning of the fourth month Aadi of the Tamil calendar.

The new moon day of this month is celebrated as "Aadi Amavasai" and the pooram star of this month is celebrated as "aadi pooram" as the birthday of Aandal. It is celebrated in all temples in a grand manner.

The 18th day of this month is celebrated as "Aadi perukku" or "Pathinettam perukku". Since rain flows in this month, the rivers are filled with water. People will assemble to nearby river or beach with friends and celebrate this festival in a grand manner.

This is the festival when the river is worshipped as the embodiment of woman falls on the 18th day of Adi (July-August). At embankments on rivers, in olden days when dams were unknown, women from farming families prayed to the river to flow perennially to enable them raise three crops in the year. Newly weds are on this day offered special reception by the bride’s parents. Let us pray to Mother Kaveri that water flows perennially, rendering the earth fertile .

Adiperukku is a unique South Indian and specially a Tamil state festival celebrated on the 18th day of the Tamil month of Adi (mid July). The festival coincides with the annual freshes of the rivers and to pay tribute to water’s life-sustaining properties. It is celebrated near River basins, water tanks, lakes and wells etc of Tamilnadu when the water level in the rises significantly heralding the onset of MonsoonAadiperukku, water ritual through religious practice: In India the rivers Ganges and Yamuna, Cauvery and Gothavari are considered sacred. Just like the earth gives us food, water is considered as a sacred necessity to meet the needs of individuals

In madurai The Aadi Mulaikottu festival is celebrated for 10 days during this month. The festival would be confined to only to the Amman, who will be taken out in procession along Aadi streets. Spcial recitals of Nadaswaram would be the highlight of this festival.

Aadi and festival sales go hand in hand together. Interestingly the aadi sale starts from the first of july now a days and extended more into the month of Avani too. The retailers especially textiles and jewellery merchants try to cash in on the buying spree of the customers and offer attractive and hefty discounts on their products. It is also the habit the habitual purchasers to wait for the aadi discount and some of them finish their purchases for the ensuing festive seasons like Diwali and Ramzan during this aadi sale.