In Hindu calendar Shravan month is dedicated to Lord Shiva. Whole month is considered auspicious to seek blessing of Lord Shiva. Devotees keep various fasts during Shravan month to please Lord Shiva.
Shravan month is also known as Sawan month in North Indian states. All Mondays or Somwar(s) which fall during Shravan month are considered highly auspicious for fasting and known as Shravan Somwar or Sawan Somwar Vrats. Many devotees observe sixteen Mondays or Solah Somwar fasting from first Somwar of Sawan month.
All Tuesdays or Mangalwar in Shravan month are dedicated to Goddess Parvati, the consort of Lord Shiva. Tuesday's fasting during Shravan month is known as Mangal Gauri Vrat. Sawan Shivaratri and Hariyali Amavasya are other auspicious days during Shravan month.
Notes: All timings are represented in 12-hour notation in local time of New Delhi, India with DST adjustment (if applicable).
Hours which are past midnight are suffixed with next day date. In Panchang day starts and ends with sunrise.
There is fifteen days difference in starting time of Shravan month depending on the followed lunar calendar in the region. In Purnimant calendar, usually followed by North Indian states, Shravan month starts fifteen days before Amavasyant calendar.
In Andhra Pradesh, Telangana, Goa, Maharashtra, Gujarat, Karnataka and Tamil Nadu, Amavasyant Lunar Calendar is followed while in North Indian states Rajasthan, Uttar Pradesh, Madhya Pradesh, Punjab, Himachal Pradesh, Uttarakhand, Chhattisgarh, Bihar and Jharkhand Purnimant Calendar is followed. Hence half of the Sawan Somwar dates differ in both calendars.
In Nepal, and some parts of Uttarakhand and Himachal Pradesh, Sawan Somwar is observed as per Solar Calendar. Hence, Sawan Somwar dates in these regions might differ from Amanta as well as Purnimant calendar.