Why Festival Dates Differ in the USA, UK and Australia

Diwali on different days in Delhi and New York? The panchang is read at your local sunrise — here is exactly why festival and vrat dates shift abroad, and how to find yours.

The one-line answer

Hindu festival dates are not fixed calendar dates — they are tithis (lunar days), and a tithi is observed on the civil day when it prevails at your local sunrise. Sunrise in New York happens about nine and a half hours after sunrise in Delhi, so the tithi prevailing at sunrise can differ — and with it, the festival date.

How a tithi works

A tithi is the time the Moon takes to gain 12° of longitude over the Sun — roughly 20 to 26 hours, drifting against the clock. It can start at 4 PM and end at 2 PM the next day. Since it rarely aligns with midnight-to-midnight civil days, tradition anchors observance to sunrise: whichever tithi is running when the sun rises at your location governs that day.

Because the same instant of tithi-change is a different local time in each timezone, two cities can genuinely observe the same festival a day apart. Neither is wrong — each is correct for its own sky.

A concrete example

Suppose Amavasya ends at 7:10 AM IST. In Delhi (sunrise ~6:00 AM), Amavasya prevails at sunrise — observed today. In London that same instant is 1:40 AM; at London sunrise Amavasya has already ended — so London observes it the previous civil day. Same Moon, different sunrise, different date.

What you should actually do

Use a panchang computed for your own city, not an Indian one. Our city pages compute sunrise, tithi, nakshatra and rahu kalam for your coordinates and timezone, and show side-by-side whether today's tithi matches India's.