How Rahu Kaal is calculated
The daytime — sunrise to sunset — is divided into eight equal parts. Each weekday, one of these eight parts belongs to Rahu. The first part of the day is never Rahu Kaal; the other seven are shared out among the seven weekdays:
| Weekday | Part of the day | Clock time if sunrise is 6:00 am and sunset 6:00 pm |
|---|---|---|
| Monday | 2nd | 7:30 – 9:00 am |
| Saturday | 3rd | 9:00 – 10:30 am |
| Friday | 4th | 10:30 am – 12:00 noon |
| Wednesday | 5th | 12:00 noon – 1:30 pm |
| Thursday | 6th | 1:30 – 3:00 pm |
| Tuesday | 7th | 3:00 – 4:30 pm |
| Sunday | 8th | 4:30 – 6:00 pm |
A popular English mnemonic for the order from Monday's slot onwards is "Mother Saw Father Wearing The Turban on Sunday" — Monday, Saturday, Friday, Wednesday, Thursday, Tuesday, Sunday.
The 6-to-6 times are only an illustration. In Delhi in December, with sunrise near 7:10 am and sunset near 5:30 pm, each part is about 77 minutes and every Rahu Kaal shifts accordingly. Always use your local sunrise and sunset, or a panchang made for your city.
Why Rahu, and why it matters
Rahu is the north lunar node — the point where the Moon's path crosses the Sun's, and so the point where eclipses happen. In the Puranic story of the churning of the ocean, the asura Svarbhanu slipped into the line of gods to drink amrit; the Sun and Moon exposed him, Vishnu severed his head with the Sudarshan chakra, and the immortal head became Rahu, who swallows the Sun and Moon in eclipses ever after. Rahu therefore stands for obscuration, illusion and sudden reversals — not what you want at the start of something new.
Observance is strongest in South India, where Rahu Kaal is printed in every calendar and many people will not start a journey, sign a contract or begin an important task during it.
What to avoid, and what is fine
- Avoid starting: a journey, a business, a purchase of property or vehicle, an interview, a contract, or any ceremony such as griha pravesh or engagement.
- Not affected: work already in progress. Rahu Kaal is about beginnings; you do not need to stop working or travelling because it has begun.
- Routine worship is fine. In fact, in Tamil Nadu and Karnataka, Rahu Kaal Durga puja — lighting lamps to Durga during Rahu Kaal, especially on Tuesdays and Fridays — is a well-loved practice, on the reasoning that the Goddess overcomes Rahu.
Related daily periods
South Indian panchangs also list Yamaganda and Gulika Kaal, two more daily periods calculated the same way from the eight parts of the day. Yamaganda is treated as inauspicious like Rahu Kaal. Gulika (Mandi, the "son of Saturn") is unusual: whatever is begun in it is said to repeat, so it is avoided for anything you would not want to happen twice — but some choose it to buy assets.
Keeping it in proportion
Rahu Kaal is a short daily window, not a curse on the day. If an unavoidable start falls in it — a train time, a hospital appointment — a brief prayer to Ganesha as remover of obstacles before you set out is the traditional response.