According to Hindu calendar, the month of Shravan is dedicated to Lord Shiva. The entire month is considered highly auspicious to worship Lord Shiva for his blessing. Devotees observe a number of fasts during Shravan month to appease Lord Shiva.
In North India, Shravan month is also known by the name Sawan month. All Mondays or Somwars in Shravan month are regarded as highly auspicious for fasting and they are known as Shravan Somwar or Sawan Somwar Vrats. There are several devotees who observe sixteen Mondays or Solah Somwar fasting from the first Somwar of Sawan month.
All Tuesdays or Mangalwar in Shravan month are devoted to Goddess Parvati. Fasting observed on Tuesdays in Shravan month is known as Mangal Gauri Vrat. Other auspicious days in Shravan month include Sawan Shivaratri and Hariyali Amavasya.