Hindu Heritage Calendar - 2025

Hindu Heritage Services will offer precise online event dates for Hindu heritage festivals, calculated according to Eastern Standard Time (EST) and verified by knowledgeable priests from the New England area.

This service is designed to help community members confidently plan and participate in festival events with accuracy and ease.

Eastern Daylight Time (EDT)

Misconception

"The Indian Hindu festival observance date, based on the Indian calendar (panchanga), applies universally around the world."

This is a common misconception. The observance dates given by the Indian panchanga are specific to India and should not be directly applied to other locations globally. The panchanga is based on the local time in India, and the same dates and times do not automatically translate to other countries.

Another misconception arises due to time zone differences. Many assume that because countries like the USA, Canada, or European nations are behind India in time, festivals will be observed a day later. This is incorrect. Tithis, Nakshatras, Yogas, and Karanas are astronomical events that occur at the same moment universally, regardless of time zone.

These events are based on the geocentric positions of the Sun and Moon, which do not change across the globe. Once you account for local time zones, the festival observance date may differ.

For instance, in countries west of India, the festival might fall on the previous day, while in countries east of India, it could fall on the following day. Local factors like sunrise, sunset, moonrise, and moonset times are used, along with the tithi, to determine the exact day for the festival. This is why sometimes festivals may appear to fall on the same day as in India, or a day earlier or later, depending on the country.

Key Points

A Hindu day (Vaara) begins at sunrise and ends at the next sunrise—not at midnight. The Hindu date (tithi) also changes at sunrise and is not fixed to a 24-hour cycle. It can range from 19 to 26 hours, depending on the Moon's position relative to the Sun.Tithi, Nakshatra, Yoga, and Karana are based on the Sun and Moon's geocentric positions, which occur simultaneously everywhere on Earth. These events, therefore, begin and end at the same moment worldwide.

However, we must convert these times to local time zones.In India, panchang makers convert these times to Indian Standard Time (IST). Similarly, other countries must adjust the times to their own local time zone (often using UTC as the reference).Example:Take October 17th, 2008. On this date, the Ashwayuja (Ashwin) Krishna Paksha tithi Tritiya ends at 16:39:21 IST, and Chaturthi begins immediately after.

In India, Tritiya is still prevailing until 16:39 IST.Now, consider the time difference between India and Seattle, USA. Seattle is 13 hours 30 minutes behind India (with daylight saving time, the difference is 12 hours 30 minutes). To convert the time, subtract 12 hours 30 minutes from 16:39:21 IST, which gives you 04:09:21 AM (October 17th) in Seattle. Therefore, after 4:09 AM, Seattle will be observing Chaturthi (not Tritiya).

This illustrates that festivals do not wait for a specific time zone to "catch up." The Sun rises at different times across the world, and we must use local times for sunrise, sunset, moonrise, and moonset, along with tithi and nakshatra end times, to accurately determine the festival dates and times.

Festival Calculation Example:For festivals like Sankathara Chaturthi (Karwa Chauth), the tithi must be prevailing during moonrise. In New Delhi, for example, moonrise might occur at 19:36 PM, while in Kolkata, it could be at 19:25 PM. Suppose Tritiya ends at 19:32 PM IST. In this case, people in Kolkata will celebrate Sankathara Chaturthi the following day, while those in New Delhi will celebrate on the same day.

In essence, the panchanga uses the end times of tithi and nakshatra, along with specific Sun and Moon positions, to determine festivals, but these timings must be converted to the local time zone for accurate observance.

All the tithi calculations on this site are based on vrat (fasting) days. For tithi calculations specific to Shraddha (ancestral rituals), please reach out to us.