Mahashivratri is one of the biggest festivals of Hindus. As per the South India Panchangam (Amavasyant Panchang), Maha Shivratri is celebrated on the 14th day of the dark fortnight in the Magha month. On the other hand, as per the Panchang of North India (Purnimant Panchang), festival of Maha Shivaratri is observed on the 14thday of the dark fortnight in the Falgun month.
As per the Panchangam of both North as well as South, Mahashivaratri be on the same day. Hence, according to Gregorian calendar, the date remains same in the whole India. On this day, devotees of Shiva worship him by gifts Bael leaves to the Shivling, keep fast, and staying awake whole night.
In order to observe Mahashivratri Vrat (fasting), following rules are mention in our scriptures:
Many stories are prevalent about Shivaratri. As per the narration, Goddess Parvati had wended a tough penance to get Shiva ji in her life as her husband. Legendary texts say - as the result of her hard efforts, Lord Shiva and Maa Parvati got married on the 14thday of the dark fortnight of Falgun. This is the cause why Mahashivratri is considered very much important as well as lucky.
Apart from this, Garuda Purana mentions the significance of this day with a different story. According to which, one day, a seeker went out to chase with his dog, but he get nothing. Being tired and hungry, he sat down near a pond. There was a Shiva Lingam under a Bilva tree. In order to give some comfort to his body, he takes some leaves from that tree. By chance, some of them fell down over the Shiv Ling. After that, he scattered the water of pond over his feet to clean them. Eventually, some of the water also got scattered over the Shiv Lingam. While doing all this, one of his arrows fell down. In order to pick it up, he bowed down in front of the Shiva lingam. Like this, he completed the whole process of Shiva Pooja on the day of Shivaratri inadvertently. After his death, when Yamadoot came to take his spirit, people from Shiva’s army came to defend him.
If the inadvertently worship of Shiva on the day of Mahashivratri gives such an amazing result, how it will bless us if we do it knowingly.
Lord of the Chaturdashi Tithi (14th day as per Hindu Panchang) is Shiva thyself. That is why, in every Hindu month, the 14th day of dark fortnight is celebrated as Masik Shivratri (monthly night of the Shiva). In astrological classics, this day is considered greatly favorable. As per the calculations of mathematical part of astrology, Mahashivratri takes place when Sun gets in Uttarayana and change of season also goes on. Astrology tells that on the 14th day, Moon gets weaker. As Lord Shiva has founded Moon over his forehead, worshipping Him accredit the Moon of the worshipper. As Moon is the signification of mind, it gives an additional advantage. In other words, worshipping Shiva gives strength to the will-power and supreme valor as well as toughness in the devotee.