Maha Shivaratri is a Hindu festival celebrated annually in honour of the god Shiva. The name also refers to the night when Shiva performs the heavenly dance called Tandava. In every month of the luni-solar Hindu calendar, there is a Shivaratri – "night of Shiva" – on the day before new moon
In the scriptures, Monday and Pradosh day is considered best for worshipping Lord Shiva. Shivratri is celebrated on the Chaturdashi Tithi of Krishna Paksha every month. It is also called Pradosh. According to the Hindu calendar, Badi Shivaratri is celebrated when Pradosh falls in the month of Shravan. In this case, there are 12 Shivratri in a year.
The Shivaratri that falls on the Chaturdashi date of the Krishna Paksha of Phalguna month is called Mahashivratri. This day is celebrated with pomp all over the country. According to Shiv Purana, the Chaturdashi of Krishna Paksha of Phalguna month is called Mahashivratri. The festival of Mahashivratri is celebrated to commemorate the marriage of Lord Shiva and Goddess Parvati. That's why Shiva devotees consider this day to be very special.