The day of Purnima is the day in each month in which the full moon occurs, and marks the division in each month between the two lunar fortnights. The Shukla ("bright") Paksha is the fortnight before, and the Krishna ("dark") Paksha is the fortnight after Purnima. Chaitra Purnima is the Purnima day of the first month of the Tamil year. This auspicious date attracts many to do Giripradakshina. It is celebrated on  April 5, 2023.  

This festival is also known as Diwali, Divali, and the Festival of Lights. It is celebrated twenty days after the tenth and final day (known as Dasara) of Navaratri (see below). Deepavali is an ancient festival that signifies the victory of light over darkness. You will see many lights inside and outside of homes, and fireworks. Gifts are exchanged. The festival covers a five-day period, but the main festival night coincides with the darkest, new moon night of the Tamil month Kartika. It is celebrated November 12 in 2023.

On the night of every full moon, about 300,000 people (many of these are pilgrims from out of town) make the Giripradakshina circuit. During the Karthagai Deepam full moon, you may see a million people on Giripradakshina. This is a reflection of the belief that Arunachala’s power is at its peak during this night.

This festival is dedicated to gratitude and appreciation for one's guru, or spiritual teacher. Special pujas are performed at ashrams and temples around Arunachala. The power of the guru to liberate their students is said to be 1000 times stronger on this day. On this night, Saivite devotees worship their guru Lord Shiva by walking around Arunachala barefoot. This festival is determined by the lunar calendar. It is celebrated on July 3rd 2023.

To celebrate the sacredness of Arunachala, every year the Holy Beacon (a huge pot of oil) is lit on the summit of Arunachala during the Tamil month of Karthigai (mid-November to mid-December). The Beacon is known traditionally as Karthigai Deepam. It stays lit for 9-13 days and can be seen from a long distance. Around a million pilgrims are drawn to this festival to have darshan of the Karthigai Deepam and to do Giripradakshina. Since this day invariably falls on a full-moon day, the earthly delight and spiritual auspiciousness are doubled.

To witness the festivities of Karthikai Deepam, the deity Lord Arunachaleshwara Himself, who is ‘Giripradakshinapriya’ (one who loves going around the Hill of Arunachala), sets out on Giripradakshina on the third day after the festival of the Holy Beacon, in the company of His consort Apithakuchamba and other deities like Ganesa and Subramanya. At this time, the deities from both the temples on the East (Tiruvannamalai) and West (Adiannamalai) go in a procession around the Hill in large ornate carts pulled by masses of devotees. Lord Arunachaleshwara also goes around the Hill alone during the Tiruvoodal Festival (see below), which falls in mid-January every year, during Pongal.

It is believed that on special holy days like Karthkai Deepam, or Maha Shivarathri, an invisible host of etheric siddhas and rishis accompanies the pilgrims on their Giripradakshina. Authoritative references to this fact are found in the Vedas, Puranas, Stotras, and other scriptures. This festival is determined by the lunar calendar. In 2023, it starts November 17 and culminates with the full moon with lamp lit at the top of Arunachala on November 26.

This translates as "the great night of Shiva". Devotees of Shiva stay up all night doing worship practices and fasting. In Tiruvannamalai, you will see devotees walking barefoot around Arunachala throughout the day and night. Many temples, shrines, and ashrams around Tiruvannamalai are open all night.

The festival of Maha Shivaratri falls varyingly in February or March, to coincide with the bright half of the Hindu calendar month Maagha. This is a very important, spiritually significant festival that re-enacts the story of Brahma, Vishnu and all other deities paying homage to the Column of Fire Lord Shiva created after their pride has been humbled. At their request, Lord Arunachala, out of compassion changed from a column of fire to a lingam (the mountain as it exists now).

The Arunachaleshwara Temple gates open around 2 a.m. in the early morning of Shivaratri day. After the initial abhishekam is performed, the puja, and Laksharchana commences and continues till late afternoon. The Temple is kept open the whole night with pujas at three-hour intervals, the first of which is held at six in the evening. On this particular event, people go for Giripradakshina through the day and night, each according to their fervour. Some even do Giripradakshina continuously without stopping throughout the night, more than once.

The standard calendar date for this festival varies due to being determined by the Tamil lunar calendar. It was celebrated February 18 in 2023.

This is a festival dedicated to the worship of the deity Durga. The word Navaratri means 'nine nights' in Sanskrit. During these nine nights and ten days, nine forms of Shakti or Devi are worshiped. This festival is determined by the lunar calendar. It starts on October 15th 2023. 

Pongal is perhaps the most universally celebrated festival in Tamil Nadu, and Tiruvannamalai is no exception. It is a harvest festival honoring the sun god and god of rain, Indra. Pongal means "boiling over", in other words, a boiling over of the bounty of the harvest. It is celebrated over a period of 3 days, with great fanfare in Tiruvannamalai, including fireworks, parades, blowing of horns and beating of drums. You will see fires in the streets due to old clothes being burned, replaced by new ones. A few days prior to the start of the festival, every house is cleaned, whitewashed, and dusted. Many old or broken items are replaced. Kolams (colored patterns on the doorsteps of homes) created during Pongal are very elaborate. During this festival, a special dish called Pongal is prepared. Since this festival depends on the solar cycles, its date is fixed in the standard calendar every year. It is celebrated on the 13th of January every year.

This celebration is known as "Puthandu" in Tamil. Feasts are enjoyed in homes, and elaborate kolams are displayed in front of homes. This festival is determined by the solar calendar. It is celebrated on April 14 every year.

This is a festival to celebrate the divine quarrel between the Lord Arunachaleshwara and his consort Apithakuchamba, and Saint Sundarar’s efforts to reconcile their differences. It is held the day after Makar Sankranti or Pongal (see below) day in the month of January. Pongal day usually falls on the 14th or 15th of January.

The importance of the Tiruvudal festival is that the Lord will not come on any chariot or any vahanam, but 40 people will carry the Lord on their shoulders. In the early hours of the morning, after the Maha Deeparadhana has been performed, the deity is seated on the Kedaya. Thereafter, 40 persons carry the Lord on their shoulders to the mantapam outside the temple. An additional feature of celebrating the Lord is a huge umbrella that is held out to shield the Lord. The combined weight of the Lord and the umbrella is in tons, and it is sheer Grace of Lord Arunachaleswara that the men are able to bear the weight. The Lord makes three rounds of the temple. Afterwards, in the evening, the Tiruvudal festival is celebrated. This festival assumes another importance in that it is Lord Arunachaleswara giving darshan in the form as Brahma, Lord Vishnu, and Lord Rudra.

There are a number of organizations involved in conservation of Arunachala. Here is a partial list of these organizations:

• Annamalai Reforestation Society
• Arunachala Village Forest Plantation
• Tamil Nadu Forest Department
• Forest Way
• Shanti Malai

These organizations are trying to reverse deforestation and promote sustainable ecological solutions through planting, education, and sometimes, fighting fires. They also collect garbage and maintain small parks along the Giripradakshina path.

Arunachala is officially a Forest Preserve area but is under intense environmental pressure, due partly to the numbers of people visiting. Arunachala has also been degraded by being stripped of vegetation over the years by locals seeking firewood and thatching for houses, grazing by goats and other animals, unlawful fire burning for rituals, etc.

Deforestation has serious consequences not just for the natural beauty of the place, but also for water availability in the local area. The water table in Tiruvannamalai is experiencing a growing net decrease due partly to the inability of the Hill to capture and retain water. If Arunachala were properly forested, the soil on it would act like a sponge and retain rainwater better, so that the water table could remain at sustainable levels. It would also prevent flood damage. Housing developments also have the potential to re-route water runoff from the Hill so that it cannot reach the tanks and lake beds.

Your help is needed to fund projects such as those listed above to conserve and protect Arunachala from environmental degradation.