Skanda Sashti History, Significance & Rituals of Auspicious Day
Source: https://www.news18.com/news/lifestyle/skanda-sashti-2021-history-significance-and-rituals-of-auspicious-day-3651860.html

Skanda Sashti is an important festival for the Hindus as it is dedicated to Lord Skanda, the God of war and son of Shiva and Parvati. Lord Skanda is known by several names including Murugan, Kartikeyan, and Subramanya. The festival is observed on the Sashti Tithi of Shukla Paksha every month. Skanda holds special reverence among Tamil Hindus and is considered the younger brother of Lord Ganesha in south India, while in north India he is said to be the elder brother of Ganesh

Skanda Sashti: Significance

Lord Murugan is known for eliminating demons named Soorapadman and his brothers Tarakasura and Simhamukha and Sashti Tithi of Shukla Paksha marks his victory over them. It is said that Lord Murugan severed the head of Soorapadman using his weapon called Vel or Lance. Two birds emerged from the severed head - a peacock that became his vahana and a rooster that became an emblem on his flag.

By keeping fast or vrat on Skanda Sashti day, devotees pay their tributes to the Lord for killing the demon and restoring peace.

Skanda Sashti: Ritual

Devotees on this day get up early, take a bath, worship Lord Murugan and observe a fast for the whole day. They offer an oil lamp, incense sticks, flowers, kumkum, etc to him. Some devotees also visit a temple to offer their prayers.

As per the rituals, fasting begins with sunrise and is broken on the next day morning. Also, the method of fasting depends on an individual as some observe a full-day fast while others undertake partial fasting.
Source: https://en.wikipedia.org/wiki/Sura_Samhaaram

Sura Samhaaram

Sūra-saṃhāraṃ or soora-samharam also known as Skanda ṣaṣṭhi or kanda sashti, is the most important festival dedicated to Lord Murugan. Kanda Sashti is observed mainly by Tamil Hindus. The day of Kanda Sashti is decided based on lunar month and it falls during sixth day of Karthikai Month (Karthikai Masam in Tamil).

During Kanda Sashti, devotees observe six days fasting which starts from first day or Pirathamai ( called prathamā in northern Hindu calendar ) of Aippasi lunar month and ends on the sixth day which is known as Soorasamharam day. Soorasamharam is the final and the most important day of the six days festivities. It is believed that Lord Murugan defeated Demon Surapadman on the very same day and the festival of Soorasamharam is observed every year to mark the victory of good over evil.

It is important to note that the day when Shasti Tithi conjugates with panchami tithi is chosen for Soorasamharam vratam. Hence most temples observe Kanda Sashti on panchami tithi if Shasti Tithi starts before sunset on panchami Tithi.

Kanda Sashti celebrations at Thiruchendur Murugan Temple are the most famous one. The six days celebrations which start from Pirathamai of Aippasi Masam culminate on Soorasamharam day. Thiru Kalyanam is observed on the next day of Soorasamharam

Temple idol procession in Vennanthur during the festival of Soora Samhaaram

Every year temple idol procession is taken out in cities during the festival of Soora Samhaaram