Notes: All timings are represented in 24+ hour notation in local time of Columbus, United States with DST adjustment (if applicable).
Hours past midnight are higher than 24:00 and fall on next day. In Panchang day starts and ends with sunrise.
Pradosha Vrat is observed on both Trayodashi Tithis, i.e. Shukla Paksha Trayodashi and Krishna Paksha Trayodashi, in lunar month. For Pradosham Vrat, day is fixed when Trayodashi Tithi falls during Pradosha Kala which starts after Sunset. The time window after Sunset when Trayodashi Tithi and Pradosha time overlaps is auspicious for Shiva Puja.
When Pradosham day falls on Thursday, it is known as Guru Pradosha. Guru Pradosha is also known as Brihaspati Pradosha. This fast is considered important for spiritual growth and the attainment of religious knowledge. While the day is dear to Lord Shiva, it is also associated with Devguru Brihaspati. Therefore, observing the fast on this day brings wisdom, education, wealth, righteousness, and overall prosperity.
Additionally, marriage, children, teachers, elder brothers, fathers, and charity are also governed by the planet Brihaspati. Hence, observing the Pradosha Vrat on this day helps a person progress in all these areas. This fast is especially considered beneficial for spiritual seekers and students.