While Hanuman Chaturthi is celebrated on the Purnima Tithi of the Chaitra month, some parts of the country worship Lord Hanuman on the Chaturdashi Tithi of the Karthik month, which comes a day before the Diwali Puja. The day of Hanuman Puja coincides with Kali Chaudas, which is believed to be the night when bad spirits are the most powerful. Lord Hanuman is worshipped not only to protect us from these bad spirits but also to seek strength and power.
Lord Hanuman was a pure devotee of Lord Rama and helped him immensely during his lifetime. Lord Rama was so pleased with Lord Hanuman’s dedication towards him that he blessed him to be worshipped before him. And that’s why Hanuman Puja is observed a day before Diwali.
In some parts of the country such as Hanumangarhi temple in Ayodhya, the day is observed as Shri Hanuman Jayanti. According to Kashi Jyotishacharya Chakrapani Bhatt, the Chaturdashi Tithi in the Krishna Paksha of the Karthik month will begin on October 23, Sunday from evening 5:04 PM. The Tithi will end on October 24 at 5:04 PM.
Therefore, Hanuman Jayanti or Hanuman Puja will be celebrated on the evening of October 23.
The auspicious time to worship Lord Hanuman starts at 11:40 PM and continues until 00:31 AM on October 23. This year, Hanuman Puja falls in the Sarvatha Siddhi Yoga and Amrit Siddhi Yoga. Sarvatha Siddhi Yoga is for the whole day on Hanuman Puja, while Amrit Siddhi Yoga is from 2:34 PM to 06:27 AM the next day. Apart from this, Indra Yoga will also fall on this day from morning till evening at 16:07.