The seven days of the week are governed by different planets. In order to get over the malefic effects of a particular planet or to achieve the blessings of a particular god, Vaar Vrat is observed on that particular day.
As per Hindu Scriptures and beliefs, each day of a week is dedicated to each God.
There is a story associated with each day known as Vaar Vrat Katha.
1. Ravivaar Vrat: Fasting is observed on Sundays to get the blessings of Lord Surya. It is believed that the person observing this vrat will receive honour and fame and achieve success over his enemies.
Surya Bhagavan or Goddess Saraswati is also worshipped on Sundays (Ravivaar Vrat).
Bada Itvaar (Sundays in Bhadrapad Month) and Paush Itvaar (Pushya Aadivara Vratham) are few among popular Ravivaar vrat.
2. Somvaar Vrat: Fasting is observed on Mondays to get the blessings of Lord Shiva and the planet Moon. It will help the person to have a happy married life or find a suitable marital partner.
Lord Shiva is worshipped on Mondays.
Shravan Somvar Vrat, Kartika Somavaram Vratham, Solah Somvar Vrat are few among the popular Somvar Vrat.
3. Mangalvaar Vrat: Fasting is observed on Tuesdays to overcome the malefic effects of Mars and get the blessings of Lord Hanuman.
Ganesha Puja or Gauri Puja, or Subramanya Puja (Murugan Puja) is performed on Tuesdays.
Mangala Gauri Vratham is the popular Mangalvaar Vrat.
4. Budhvaar Vrat: Fasting is observed on Wednesdays to overcome the malefic effects of the planet Mercury and Lord Shiva is also worshipped during the occasion.
Sri Krishna Puja or Vittal Pujan or Ayyappa Puja or Saraswati Puja is also observed on Wednesdays.
5. Guruvaar Vrat : Fasting is observed to get the blessings of planet Jupiter. It is believed that fasting on Thursdays will promote greater learning and prosperity.
Lord Vishnu, Lord Dakshinamurthy, Lord Dattatreya, or Shirdi Saibaba is worshipped on Thursdays.
6. Shukravaar Vrat: Fasting is observed on Fridays to get the blessings of planet Venus. This will help the person lead a happy and peaceful life.
Santoshi Mata Puja or Lakshmi Puja is also performed on Fridays.
Shravan Shukravaar Vrat (Shravan Mahalakshmi Pujan), Ashada Lakshmi Puja (Ashada Fridays), Varalakshmi Vratham, etc are few among popular Shukravaar Vrat.
7. Shanivaar Vrat: Fasting is observed on Saturdays to overcome the malefic effects of planet Saturn and get the blessings of Shanidev. It helps overcome all problems in life.
Lord Hanuman or Lord Balaji (Sri Venkateswara Swamy) is also worshipped on Saturdays.