A tithi can begin or end at any hour, but a calendar needs one name per day. The tradition solves this with a simple rule: the tithi running at sunrise names the whole day. This lesson explains that rule, its two exceptions, the observances that look at other times of day, and why two cities can show different dates for the same festival.
The day begins at sunrise
In the Panchang a day runs from one sunrise to the next, and sunrise itself needs a definition. The US Naval Observatory defines sunrise as the moment the upper edge (limb) of the Sun’s disc appears on the horizon, allowing for average atmospheric refraction, which lifts the Sun’s image by roughly half a degree. Some almanacs instead use the moment the centre of the disc reaches the horizon.
The two choices differ by a few minutes. So the definition varies slightly between almanacs, and this site documents its own choice on its methodology page. When a tithi ends within a few minutes of sunrise, that choice can decide which tithi names the day.
Udaya tithi: the tithi at sunrise names the day
Udaya tithi means “the tithi at sunrise”. Whatever tithi is current at the moment of local sunrise is the tithi of that day until the next sunrise, even if it ends soon afterwards. Example: sunrise is at 06:20, and Shukla Panchami ends at 07:05, when Shashthi begins. The calendar calls the day Panchami, although Shashthi runs for almost all of it.
Kshaya and vriddhi tithis
Tithis last roughly 20 to 27 hours, while days last about 24, so the two cycles slip against each other. A short tithi may begin just after one sunrise and end before the next. It then touches no sunrise, and no day is named after it: a kshaya (lost) tithi. Example: on Monday Dwitiya runs until 06:30, just after the 06:00 sunrise; Tritiya runs from 06:30 Monday to 05:40 Tuesday; at Tuesday’s sunrise Chaturthi is running. Monday is Dwitiya, Tuesday is Chaturthi, and Tritiya is kshaya.
The opposite happens with a long tithi. If it begins just before one sunrise and ends just after the next, it is current at two sunrises, and two consecutive days carry its name: a vriddhi (increased) tithi. The calendar then shows, for example, two Saptamis in a row, and further rules decide on which of them an observance falls.
Observances that use other times of day
The sunrise rule names the day, but many observances look at the tithi at another time. The texts on festivals specify which part of the day matters:
- Ekadashi fast: the Smarta rule generally follows the Ekadashi current at sunrise. The Vaishnava rule is stricter: if Dashami is still running at arunodaya, about 96 minutes (4 ghatis) before sunrise, the Ekadashi is held to be touched by Dashami and the fast moves to the next day. The two can fall on different days.
- Janmashtami: Krishna’s birth is celebrated when Ashtami prevails at nishita, the midnight period; many traditions also look for Rohini nakshatra.
- Pradosh vrat: kept on the day when Trayodashi prevails during pradosh kaal, the period just after sunset.
- Ganesh Chaturthi: the Chaturthi that prevails at madhyahna, the middle of the five equal parts of daylight, is preferred.
So a festival can fall on a day whose sunrise tithi is a different one. The site’s festival and Ekadashi lists apply these rules.
Why dates differ from place to place
A tithi ends at the same instant everywhere on Earth, because it depends only on the Sun and the Moon. Sunrise does not: it comes earlier in the east and shifts with latitude and season. Suppose a tithi ends at 06:40 IST on a winter morning. In Kolkata, where the Sun rose around 06:15, it was running at sunrise and names the day. In Mumbai, where sunrise came around 07:05, the next tithi had already begun. One date, two different udaya tithis.
That is why a Panchang must be calculated for your location, and why festival dates in India and abroad can differ by a day. The panel below shows today’s five limbs for your place; compare the tithi’s end time with your sunrise to see which tithi names the day.
ಪ್ರಯತ್ನಿಸಿ: ನಿಮ್ಮ ಸ್ಥಳದಲ್ಲಿ ಇಂದಿನ ಪಂಚಾಂಗ
ಈ ಸ್ಥಳಕ್ಕೆ ಸೂರ್ಯೋದಯದಲ್ಲಿ ಇಂದಿನ ಐದು ಅಂಗಗಳು:
- ಸೂರ್ಯೋದಯ
- ತಿಥಿ
- ಅಷ್ಟಮಿ (ಕೃಷ್ಣ ಪಕ್ಷ)
- ವಾರ
- ಸೋಮವಾರ
- ನಕ್ಷತ್ರ
- ಆಶ್ಲೇಷಾ
- ಯೋಗ
- ಶುಭ
- ಕರಣ
- ಕೌಲವ
ಪ್ರತಿ ಅಂಗವೂ ದಿನದಲ್ಲಿ ಬದಲಾಗಬಹುದು; ಪಂಚಾಂಗ ಪುಟವು ಅಂತ್ಯ ಸಮಯಗಳನ್ನು ತೋರಿಸುತ್ತದೆ. ಇಂದಿನ ಪಂಚಾಂಗ ತೆರೆಯಿರಿ
Amanta and Purnimanta months
Lunar months are named in two ways. In the Amanta system, used widely in western and southern India (for example Maharashtra, Gujarat and Karnataka), a month ends at Amavasya. In the Purnimanta system, common in North India, a month ends at Purnima. The bright fortnight has the same month name in both, but the dark fortnight is named one month later in Purnimanta. The dark half Amanta calls Shravana Krishna is Bhadrapada Krishna in Purnimanta, so Janmashtami, a Krishna Ashtami, falls in “Shravana” in one calendar and “Bhadrapada” in the other: the same day, two names.
Neither system is wrong; they label the same tithis differently. Almanacs also differ in their sunrise definition, ayanamsa and festival rules, so a one-day difference between two careful calendars usually comes from one of these choices rather than from an error.