Most panchang apps and printed calendars are built for India and default to IST. Reading them correctly from a US time zone takes one extra step most people skip.

The mistake: converting the clock time instead of recomputing

Simply subtracting 9.5 to 13.5 hours (depending on the US time zone) from an IST muhurat window does not give you your local muhurat. Tithi, nakshatra, sunrise and sunset are all tied to your actual location, they need to be computed for your city, not translated from India’s numbers.

What changes for a US city

Sunrise and sunset times, which anchor Rahu Kaal, Abhijit Muhurat and several other windows, depend on your city’s own latitude and longitude. A city like Seattle has very different day-length swings across the year compared to Chennai, which changes when these windows fall.

A concrete example of why the math breaks

Take Rahu Kaal, the roughly 90-minute inauspicious window computed by dividing daylight hours into eight parts and picking the segment tied to the day of the week. On a mid-January day, sunrise in Chennai is around 6:28 AM and sunset around 5:58 PM, giving about 11.5 hours of daylight. In Chicago the same week, sunrise is closer to 7:20 AM and sunset around 4:50 PM, giving under 9.5 hours of daylight.

Divide each by eight and the segments are different lengths: roughly 86 minutes per segment in Chennai versus 71 minutes in Chicago. Rahu Kaal isn’t a fixed clock time you can shift by an offset, it’s a fraction of that day’s actual daylight, and the daylight itself is a different length in the two cities. Subtracting 10.5 hours from Chennai’s Rahu Kaal window to “get” Chicago’s window gives you a number that has nothing to do with Chicago’s actual sunrise and sunset that day.

The gap gets bigger in summer. A Seattle June day can run close to 16 hours of daylight against Chennai’s fairly stable 12-13 hours year-round, since Chennai sits much closer to the equator and its day length barely swings across seasons. A US city far from the equator sees far more seasonal variation, which means the size of each Rahu Kaal or Abhijit Muhurat segment shifts noticeably month to month in a way it barely does in most of India.

Daylight saving adds a second layer

US clocks shift in March and November; India’s don’t observe DST at all. This means the relationship between your local clock time and IST changes twice a year, not just the raw hour offset. A muhurat window that converted cleanly to 8:15 PM Eastern in July can land at a different clock minute in December once the DST shift and the changed day length both apply. If you’re planning something months ahead, such as a wedding muhurat or a griha pravesh date, don’t lock in a clock time early and assume it holds. Recompute closer to the date, or use a tool that already accounts for your city’s coordinates and the correct DST rule for that specific day.

Getting it right

Use the panchang page or muhurat page and select your actual US city (or the nearest listed one in your time zone), rather than reading an India-based panchang and doing mental time-zone math.

For more on using these tools correctly from abroad, see the guide for Indians abroad.