What Is Rahu Kalam?

With sunrise at 6:00 a.m. and sunset at 6:00 p.m., each part lasts 90 minutes, and on a Monday Rahu Kalam is the second part, from 7:30 to 9:00 a.m.

Rahu Kalam, also written Rahu Kaal or Rahukalam, is a daily stretch of daylight that many Hindu families, especially in South India, set aside from new beginnings. Kalam means time. Rahu is the north lunar node, one of the nine grahas of Jyotish, a calculated point rather than a physical body, and the tradition associates it with confusion and obstruction.

The custom is about starts: a housewarming, the first day of a venture, the opening of a ceremony. Work already under way simply continues. Treat it as a living scheduling custom that many people keep out of respect, not as a measured hazard.

Daylight, from local sunrise to local sunset, is cut into eight equal parts, and each weekday has its own part. The clock times below assume a constructed day with sunrise at 6:00 a.m. and sunset at 6:00 p.m., when each part lasts 90 minutes.

A popular memory aid lists the weekdays in part order from second to eighth, Monday, Saturday, Friday, Wednesday, Thursday, Tuesday and Sunday, through the sentence “Mother Saw Father Wearing The Turban Smartly.”

Because both ends come from the Sun, the window moves with the seasons and with latitude, and it is rarely exactly 90 minutes. The method takes five steps.

1. Look up the local sunrise and sunset for the city and date.
2. Subtract sunrise from sunset to get the daylight length in minutes.
3. Divide by eight to get the length of one part.
4. Find the weekday's part number in the table above.
5. Multiply the part length by one less than that number and add it to sunrise for the start; add one more part for the end.

Picture a constructed mid-latitude city. On a winter Thursday the Sun rises at 7:12 a.m. and sets at 5:04 p.m., giving 9 hours 52 minutes, or 592 minutes, of daylight. One eighth is 74 minutes. Thursday takes the sixth part, so Rahu Kalam starts five parts, 370 minutes, after sunrise, at 1:22 p.m., and ends 74 minutes later at 2:36 p.m.

On a summer Thursday in the same city the Sun rises at 5:20 a.m. and sets at 8:40 p.m., 15 hours 20 minutes, or 920 minutes. One eighth is 115 minutes. Five parts, 575 minutes, after sunrise is 2:55 p.m., and the window ends at 4:50 p.m.

The same weekday rule produced windows of 74 and 115 minutes that do not even overlap. A printed list of fixed clock times, such as 1:30 to 3:00 every Thursday, is only a rough guide that drifts with the seasons.

Almanacs usually print two more eighth-of-daylight segments next to Rahu Kalam. Yamaganda is another caution window for new starts. Gulika, or Gulika Kalam, is read differently by lineage: some avoid it for starts, while others hold that whatever begins in it tends to recur. The calculators on this site use the part numbers below.

Choose a city and date, and the calculator finds that day's sunrise and sunset, timed at the upper edge of the Sun's disk on a standard horizon, then divides the elapsed time between them into eight equal parts. It shows Rahu Kalam, Yamaganda and Gulika in local time, with sunrise, sunset and the weekday, which follows the local civil date. Because it divides elapsed time, a daylight-saving clock change cannot distort the parts.

Where the Sun does not rise or set, as in polar day or polar night, the calculator reports that no window exists rather than inventing a 12-hour day. Hills, buildings and air conditions can move the sunrise you actually see, so treat the edges of any window as approximate.

Rahu Kalam is a scheduling tradition, not a measured risk. It is reasonable to plan a ceremony or a symbolic first step outside it if that matters to you or your family. It is never a reason to delay medical care, miss a flight, skip a deadline or put off an obligation to someone else.

Many people hold it lightly: if two times are equally convenient, they pick the one outside the window, and if only one time works, they go ahead. You never need to pay for a remedy because something happened to begin during it.

The next question is usually how Rahu Kalam relates to Choghadiya. Both cut daylight into eighths, so Rahu Kalam always coincides with one daytime Choghadiya block, but the two systems label the day independently. On a Thursday, Rahu Kalam lands on the sixth block, which Choghadiya calls Amrit, one of its most favored labels. Practitioners settle such clashes in different ways, and there is no single rule.

People also ask about Abhijit Muhurat, a midday window that the site takes as the eighth of fifteen equal parts of daylight, and about the full Panchang, which adds the tithi and nakshatra to the picture of the day.

Is there a Rahu Kalam at night? The calculator here gives only the daylight window, which is the form almanacs commonly print.

Does Rahu Kalam affect activities already in progress? In the usual reading, no. The custom concerns beginnings.

Why does my app show a different time? Apps differ in their sunrise definitions, rounding and location, and some print fixed clock times. Check that the city is right first.

Should I avoid everything during it? No. Daily life, work, travel and care go on as normal. The tradition only asks those who keep it to choose another time for an auspicious start when they can.

Rahu Kalam is a scheduling tradition, not a measured risk, and near the poles, where the Sun may not rise or set, it cannot be calculated.