Pradosh Vrat, also known as Pradosha, is dedicated to Lord Shiva. Pradosh day falls on the 13th day of a lunar fortnight. Shiva devotees observe fast from sunrise to the end of Pradosha period. The puja and rituals are performed during the twilight period. June 2016 Pradosh dates are June 2 (Thursday) and June 17 (Friday).
Pradosh as the name indicates is a period just before sunset and after sunset. The Pradosha period is between 1.5 hours before sunset and 1 hour after sunset.
It is believed that Lord Shiva and Goddess Parvati are in a pleasant mood during this period and they fulfill the wishes of the devotees.
You may also like to read