Skanda Sashti or Kanda Sashti, mainly observed by Tamil Hindus is the most significant festival dedicated to Lord Murugan. Skanda Sashti falls on the sixth day of Karthika Masam and it is usually determined based on lunar month.
Devotees of Lord Murugan observe six days fasting during Kanda Sashti, which begins on the first day or Pirathamai of Karthika lunar month and concludes on the sixth day, which is popularly known as Soorasamharam day. Soorasamharam is the most significant day of the six days celebration.
It is on this day Lord Murugan defeated Demon Surapadman and hence Soorasamharam is observed every year to celebrate the victory of good over evil.
“வேடனடா வேடன் இவன் தனிகை மலை நாடன்”
“வீரனடா வீரன் நாம் கந்தனுக்கு பேரன்”
between April 14th to May 13th
This is a Full moon day festival in the first Tamil month Chittirai (between April 14th to May 13th). Devotees observe fasting, worship God Murugan and break fast the next morning. This light [brilliance of the Poorna Chandra (full moon)] helps dispelling darkness to the souls. So Murugan worship and festival start on this day in the first Tamil month of the Tamil year. Similar celebrations as stated above take place in many Murugan temples.
May 14th to June 14th
Vaigasi is the second Tamil month in the year (May 14th to June 14th). Vaigasi is the 16th star. Lord Murugan is also called Visagan.
16th July to 16th August
Aadi is the fourth month in the Tamil year (16th July to 16th August). Krithigai is the third star. After pooja and prayer, devotees are provided lunch in the noon.
17th October to 15th November
Ippasi is the seventh month in the Tamil year (17th October to 15th November). Sashti is the sixth day after the new moon day (Amavasai Day). It is on this Sashti day the six faced Lord Subramaniyam annihilated Soorabanman the most atrocious Asuran, who imprisoned the Devas, and the Devas were liberated by the Lord. So this festival is celebrated in all Murugan Temples in the world and specially in a very grand manner at Thiruchenthur Temple beside the seaside in Thiruchenthur, Tamil Nadu. Multitude of devotees attend this festival taking place there for seven days, culminating with the sangaram (destruction of all evils) and bestowing of the Lord's grace and blessing to liberated souls.
16th November to 15th December
Karthigai is the eighth month in the Tamil year (16th November to 15th December). Thirukarthigai is the third star in the Tamil month. This festival is celebrated in all Murugan Temples all over the world and specially in a very grand manner at Thiru Annamalai Hill Temple in Tamil Nadu. In that evening special Deepa (fire which is called the "sacred thituchudar" in which from Lord Siva appeared in the sky) is placed on the hill top,Braman (God of creation) and Vishnu (Thirumal God of protection) vainly tried to trace the head and foot of that Fire and failed in their efforts. Multitude of devotees including the heads of the scared Mutts of Tamil Nadu which spread spiritualism among people in India and abroad witness this grand festival at Thiruvannamalai and attain the Grace and blessings of Lord Siva. At that night series of small lamps are lit in all Murugan Temples, and Bon Fire (called Sockappan) is lit in the compound of each temple celebrating the victory of the Lord.
14th January to 13th February
Thai is the tenth month in the Tamil year. (14th January to 13th February). Pusam is the eighth star in the Tamil month. This festival is celebrated in all Murugan temples all over the world and specially in a very grand manner at Palani Hill Temple in Tamil Nadu, Penang Hill and Waterfall Temple at Penang, Batu Caves Temple in Kuala Lumpur, Malaysia and Singapore Temple. In this festival also Lord Subramaniyam comes in procession in silver charriot. Multitude of devotees attend this festival observing fasting and penance and carrying out special prayers, offering Abishega materials, garlands, fruits etc to Lord Subramaniyam and carrying Kavadies in their shoulders, to the Lord up the hill to obtain the Lord's Grace and blessings and become cured of their disabilities, ill health, diseases, troubles etc.
14th March to 13th April
Panguni Uthiram is the holy festival for Hindus. This day falls on Panguni month (Palguni month in Sanskrit) is the last month of Tamil month calendar. Panguni Uthiram defined as Panguni month, Uthiram -natchathiram (star), Uthiram natchathiram coincides with the full moon on this day. Panguni Uthiram happens in full moon day of Panguni month (mid March – mid-April). Panguni Uthiram is an auspicious day because many divine marriages happened on Panguni Uthiram. Particularly, many devotees are celebrating Murugan on Panguni Uthiram. They used to go Murugan temple and take vratham during Panguni Uthiram.