The Two Hindu Calendar Systems
The Hindu calendar (Panchang) follows a lunar system where each month is approximately 29.5 days, based on the cycle of the moon. However, there is a fundamental difference in how North India and South India define when a lunar month begins and ends, leading to two distinct calendar systems that have coexisted for centuries.
Purnimant System (North India)
Month ends on: Purnima (Full Moon Day)
In the Purnimant system, each lunar month begins the day after the full moon (Purnima) of the previous month and ends on the next full moon. This means the month starts in the Krishna Paksha (waning phase) and ends in the Shukla Paksha (waxing phase) with the full moon.
Shravan in Purnimant:
- Begins after Ashadh Purnima (Guru Purnima)
- Ends on Shravan Purnima (Raksha Bandhan)
- The month contains both Krishna and Shukla Pakshas
- Typically falls in July-August
Amant System (South and West India)
Month ends on: Amavasya (New Moon Day)
In the Amant system, each lunar month begins the day after the new moon (Amavasya) of the previous month and ends on the next new moon. This means the month starts in the Shukla Paksha (waxing phase) and ends in the Krishna Paksha (waning phase) with the new moon.
Shravan in Amant:
- Begins after Ashadh Amavasya
- Ends on Shravan Amavasya
- The month contains Shukla Paksha first, then Krishna Paksha
- Typically starts about 15 days earlier than Purnimant Shravan
How the Dates Differ - Approximately 15 Days
Understanding the Overlap
The Purnimant and Amant systems name the same lunar days (tithis) differently because they assign them to different months. The result is that Shravan month in one system partially overlaps with a different month in the other system, creating an approximate 15-day difference in start and end dates.
Practical impact: This means that the first Monday or two of Sawan in the Purnimant system may fall outside of Sawan in the Amant system, and vice versa. A devotee in Delhi and a devotee in Bangalore may observe their first Sawan Somwar on different dates.
Important: Both systems are equally valid and scripturally supported. Neither is "more correct" than the other. Follow the system that your family and community traditionally uses.
North India vs South India Shravan Comparison
| Aspect | 🏔️North India (Purnimant) | 🌴South India (Amant) |
|---|---|---|
| Calendar System | Purnimant (Full Moon ending) | Amant (New Moon ending) |
| Month Start | Day after Ashadh Purnima (Guru Purnima) | Day after Ashadh Amavasya |
| Month End | Shravan Purnima (Raksha Bandhan) | Shravan Amavasya |
| Typical Period | Mid-to-late July to mid-August | Early-to-mid July to late July/early August |
| States Following | UP, Bihar, MP, Rajasthan, Delhi, Punjab, Uttarakhand, Bengal, Odisha | Maharashtra, Gujarat, Karnataka, AP, Telangana, Tamil Nadu, Kerala, Goa |
| Sawan Duration | Approximately 29-30 days (4-5 Mondays) | Approximately 29-30 days (4-5 Mondays) |
| Paksha Order | Krishna Paksha first, then Shukla Paksha | Shukla Paksha first, then Krishna Paksha |
Purnimant (Full Moon ending)
Amant (New Moon ending)
Day after Ashadh Purnima (Guru Purnima)
Day after Ashadh Amavasya
Shravan Purnima (Raksha Bandhan)
Shravan Amavasya
Mid-to-late July to mid-August
Early-to-mid July to late July/early August
UP, Bihar, MP, Rajasthan, Delhi, Punjab, Uttarakhand, Bengal, Odisha
Maharashtra, Gujarat, Karnataka, AP, Telangana, Tamil Nadu, Kerala, Goa
Approximately 29-30 days (4-5 Mondays)
Approximately 29-30 days (4-5 Mondays)
Krishna Paksha first, then Shukla Paksha
Shukla Paksha first, then Krishna Paksha
Which System Applies to Your Region?
Purnimant Regions (North India)
The Purnimant calendar system is followed in most of North, Central, and East India:
- Uttar Pradesh: Primary Purnimant region
- Bihar and Jharkhand: Follow Purnimant system
- Madhya Pradesh: Predominantly Purnimant
- Rajasthan: Follows Purnimant calendar
- Himachal Pradesh: Purnimant system
- Uttarakhand: Purnimant tradition
- Delhi and NCR: Follows Purnimant
- Punjab and Haryana: Purnimant system
- West Bengal: Generally Purnimant
- Odisha: Follows Purnimant calendar
- Nepal: Uses Purnimant system
Amant Regions (South and West India)
The Amant calendar system is followed in South and Western India:
- Maharashtra: Primary Amant region
- Gujarat: Follows Amant calendar
- Goa: Amant system
- Karnataka: Follows Amant calendar
- Andhra Pradesh: Amant system
- Telangana: Follows Amant tradition
- Tamil Nadu: Uses Amant-based system
- Kerala: Follows its own solar calendar (Kollavarsham) but Amant for lunar observances
Note: Some communities in border regions may follow either system based on family tradition rather than geographic location.
Practical Guidance for Finding Your Dates
If you are unsure which calendar system to follow or confused about when Sawan starts in your region, follow these practical steps to determine the correct dates for your Sawan Somwar observance.
- 1
Identify Your Calendar System
Determine whether your family or community follows the Purnimant (North India) or Amant (South/West India) calendar system. When in doubt, ask elders or your local temple priest.
- 2
Check the Start Date of Shravan
Shravan month begins on different dates in the two systems. In Purnimant, it starts after the Purnima (full moon) in Ashadh month. In Amant, it starts after the Amavasya (new moon) in Ashadh month.
- 3
Identify All Mondays
Once you know when Shravan begins and ends in your calendar system, identify all the Mondays that fall within that period. There will typically be 4 or 5 Mondays.
- 4
Verify with a Local Panchang
Cross-check your dates with a reliable local Panchang (Hindu almanac) or this website. Regional variations can also exist within the same system based on local traditions.
- 5
Confirm with Your Community
If your family has been observing Sawan Somwar for generations, follow the dates your family traditionally uses. Community consensus is important in religious observance.
Special Considerations
NRIs and Diaspora
Hindus living outside India face unique challenges in determining Sawan dates.
- Follow your family tradition: Use the same system (Purnimant or Amant) your family follows in India
- Use reliable digital panchangs: Websites like HinduLab calculate dates for any location worldwide
- Connect with local temples: Hindu temples abroad typically announce Sawan dates for their community
- Time zone matters: Tithis may start/end at different times depending on your location
Adhik Maas (Extra Month)
Occasionally, the Hindu calendar includes an extra month (Adhik Maas or Purushottam Maas) to align with the solar year. This can affect Sawan timing.
- If Adhik Shravan occurs: The extra Shravan month is not considered the "real" Shravan for Sawan Somwar
- Observe during Nij Shravan: Fast during the regular (Nij) Shravan, not the Adhik month
- Some traditions differ: A few communities observe both; follow your family tradition
- Rare occurrence: Adhik Shravan happens approximately once every 19 years
The Bottom Line: Both calendar systems are sacred and valid. Lord Shiva accepts the devotion of those who fast on Sawan Mondays regardless of which calendar system they follow. What matters most is the sincerity of your observance, not the exact calendar dates. When in doubt, follow your family's tradition or consult your local temple.