Sankashti Chaturthi moonrise time: why it decides the fast

Most fasts in the Hindu calendar are fixed by the sunrise. Sankashti Chaturthi is one of the few fixed by the moonrise. Of all the details people look up for it, the Sankashti Chaturthi moonrise time matters most, because it decides both the day of the fast and the moment it ends.

That one rule explains why the date in a family WhatsApp group so often fails to match the date in your own city.

What Sankashti Chaturthi is

Every lunar month has two Chaturthis, the fourth tithi of each half. The one in the bright half, Shukla Chaturthi, is Vinayaka Chaturthi. The one in the dark half, Krishna Chaturthi, a few days after the full moon, is Sankashti.

Both are dedicated to Ganesha. Sankashti, as the name suggests, is traditionally kept for relief from difficulty (sankat). It comes round once every lunar month, so there is one more in a year with an extra month, as 2026 has.

The rule: Chaturthi at moonrise

This is how the date is fixed, and how this site computes it:

Sankashti Chaturthi is kept on the day Krishna Chaturthi prevails at moonrise. The fast is broken after moonrise.

Notice what the rule does not say. It does not say "the day Chaturthi is current at sunrise", which is how Ekadashi and many other observances are set. The deciding moment is the evening, when the Moon rises.

In the dark half the Moon rises later each night, usually well after sunset. A tithi, meanwhile, starts and ends at a single instant that is the same everywhere on Earth, but that instant falls at a different local clock time in each city. So the question "is it Chaturthi when the Moon comes up?" can get a yes in one city and a no in another on the same calendar evening.

Why the Sankashti Chaturthi moonrise time differs by city

The clearest example is the best-known Sankashti of the year, Karwa Chauth. Here is what this site's engine gives for 2026:

City	Karwa Chauth	Moonrise
Delhi	29 October	8:11 PM
New York	28 October	7:29 PM
Los Angeles	28 October	7:58 PM
London	29 October	6:22 PM
Sydney	29 October	11:09 PM

Two things stand out.

The date is not the same everywhere. In Delhi, London and Sydney the fast falls on the 29th. In New York and Los Angeles it falls on the 28th. Nobody has made a mistake here. The rule picks the evening on which Chaturthi is current at the moment the Moon rises, and in those two cities that evening comes a day earlier than in Delhi. London is a case of its own: Chaturthi begins after the Moon has risen on the 28th and ends before it rises on the 29th, so the fast is kept on the 29th, the day Chaturthi holds at sunrise. If you follow the Indian date while living in New Jersey, you may end up keeping the fast on a different evening from the one the rule picks for where you are.

The moonrise time varies widely. The fast ends at 6:22 PM in London but not until 11:09 PM in Sydney. These are moonrise times worked out for each place, not one time converted between time zones, and you cannot get one from another by adding or subtracting hours.

This is why a moonrise time copied from an Indian almanac is of little use abroad. Even within India it shifts between cities, because the Moon rises at a different moment over Kolkata than over Ahmedabad.

The named Sankashtis

A few Sankashtis in the year carry their own names and draw far more people than the rest. One thing to know first: month names depend on the calendar. North India mostly uses the purnimanta reckoning, where a month ends at the full moon; Gujarat, Maharashtra and much of the south use amanta, where it ends at the new moon. The same dark-half Chaturthi can therefore carry two different month names. The day itself does not change, only what it is called.

Karwa Chauth

Karwa Chauth is Kartika's Sankashti, in the purnimanta naming; in the amanta calendar the same day falls in Ashvin. It is kept mainly by married women, traditionally for the wellbeing and long life of their husbands. Many unmarried women and a growing number of husbands now keep it as well.

The rule is the same as for any Sankashti, Chaturthi at moonrise, which is why the table above shows the date splitting between cities.

Sakat Chauth

Sakat Chauth is Magha's Sankashti, again in the purnimanta naming (Pausha in amanta). It is widely kept in north India, especially by mothers for their children. It is also called Til Chauth or Tilkut Chauth, because sesame and jaggery are central to the offerings. The date comes from the same moonrise rule.

Angaraki Sankashti

When a Sankashti falls on a Tuesday, it is called Angaraki Sankashti. The name comes from Angaraka, a name for Mars, the graha that rules Tuesday. Tradition counts it as especially meritorious, and in Maharashtra in particular it draws large crowds to Ganesha temples.

It does not fall in any fixed month. It happens whenever the moonrise rule lands the fast on a Tuesday, which may be once in a year, more often, or not at all.

How the fast is kept

Practice differs by region and family. What follows is the common shape of it, not a single correct version.

• The day. The fast usually runs from sunrise to moonrise. On Karwa Chauth many women first eat sargi, a meal before dawn traditionally prepared by the mother-in-law, and then go without food and, in the strict form, water until the Moon is seen.
• Degrees of strictness. Some keep a nirjala fast (no water). Others take fruit, milk, or the foods traditionally allowed on a fast. Families choose what suits them, and many adjust it for age or health.
• Ganesha puja. In the evening Ganesha is worshipped with durva grass, modak or laddoos, and the Sankashti katha, the story associated with that month's vrat.
• Karwa Chauth specifics. Women often gather in the late afternoon to hear the Karwa Chauth katha and pass the karwa, a clay or metal pot, around the circle.

How the fast is broken

The fast ends after moonrise, never before.

Once the Moon is up, an offering of water, the arghya, is made to it, often with flowers, rice and sweets. On Karwa Chauth the Moon is traditionally viewed through a sieve, and then the husband's face through the same sieve. He then offers the first sip of water and the first bite of food.

Cloud is a practical problem, particularly in London or Toronto in late autumn. Many households break the fast at the calculated moonrise time when the Moon itself cannot be seen. Others wait, or look at a live image of the Moon. Which way is right is a question for your family's custom, not for an almanac. What the almanac can tell you is when moonrise actually is where you live.

Find the date and moonrise for your city

The Sankashti Chaturthi dates for 2027 are calculated for your own location. Each one lists the date the moonrise rule picks and the moonrise time, so you are not working from another city's numbers.

For any single day, the panchang gives the tithi and the time it ends, along with sunrise, sunset and moonrise. There are city pages for New York and London. If tithis are new to you, the five limbs of the panchang explains how a lunar day is measured. You can browse the year's other observances under vrat.

Sankashti is fixed by a precise rule, and once you know the rule the mismatched dates stop looking like errors. Nothing has gone wrong. The Moon simply rises at a different time over each city.