Guide
Why Do Diwali, Holi and Other Hindu Festivals Fall on Different Dates Every Year?
Why do Diwali, Holi and other Hindu festivals fall on different dates every year? Not because of inconsistency, but because they follow a lunar calendar (the tithi system) rather than the fixed solar calendar most of the world uses day to day. Karwa Chauth, Navratri and most other Hindu festivals move the same way.
Why festival dates change every year: tithi, not date, is what's actually fixed
A festival like Diwali is defined by a specific tithi (lunar day) in a specific lunar month. For Diwali, that's Amavasya, the new moon of Kartik. It isn't tied to a Gregorian calendar date at all. A lunar month is about 29.5 days, and a solar year is about 365.25 days. Those two don't divide evenly. So the same fixed tithi lands on a different Gregorian date each year, shifting by roughly 10-11 days, before it periodically corrects.
Why some years get an extra "leap" month
To keep the lunar calendar roughly lined up with the seasons, an extra month (Adhik Maas) gets added in every so often. That's also why the yearly drift doesn't just pile up. Festivals stay within a predictable few-week range. They don't slowly migrate through the whole year, the way the Islamic calendar does.
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Why the exact time (not just date) matters too
A tithi begins and ends at a specific moment, not midnight to midnight. So the same festival can technically fall a day earlier or later, depending on where the tithi lands relative to sunrise in a specific city. That's why festival times are calculated city by city, not just once for the whole country.
What this means for planning ahead
A city's exact puja time, moonrise time or muhurat can only be worked out once that year's tithi and astronomical data are ready. That's why festival dates more than a couple of years out are only approximate, until the actual year gets closer.
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Frequently asked questions
Why does Diwali fall on a different date every year?
Diwali is fixed to a specific lunar tithi (Amavasya of Kartik), not a Gregorian date. Lunar months don't divide evenly into a solar year, so the Gregorian date shifts every year.
What is Adhik Maas?
An extra lunar month, added periodically to keep the lunar calendar roughly lined up with the solar year and seasons. It stops festival dates from drifting forever.
Why do festival times differ by city?
A tithi begins and ends at a specific moment. Its relationship to sunrise and sunset differs by location. So puja times and moonrise-based festivals are calculated city by city.
Astrology, tarot, numerology and related practices are offered for reflection and entertainment and are not medical, legal or financial advice.