Differences Between Lunar and Solar Calendars
While the modern world uses the Solar calendar as a standard, many traditional holidays and rites follow the phases of the moon (Lunar calendar).
1. System Differences
- Solar Calendar: Based on the Earth's orbit around the Sun (~365.24 days). Aligns with seasonal changes.
- Lunar Calendar: Based on the Moon's orbit around the Earth (~29.5 days per month). A 12-month year totals ~354 days.
2. Why Leap Months are Necessary
There is a ~11-day discrepancy between the Solar and Lunar years. To prevent the calendar from drifting away from the actual seasons, a 'Leap Month' is added approximately every three years to realign the systems (Lunisolar calendar).
- This is why holidays like Lunar New Year or Chuseok move back and forth on the Solar calendar every year.
3. Practical Usage Today
- Fishing and Tides: The Lunar calendar is essential for predicting tidal movements (high/low tide).
- Traditional Birthdays: Some families still celebrate birthdays on the Lunar date, which changes annually on modern calendars.
- Leap Month Birthdays: If born in a leap month, the birthday is typically celebrated in the corresponding regular month during non-leap years.
4. Major Lunar Holidays (East Asia)
- Seollal (Lunar New Year): 1st day of the 1st lunar month
- Daeboreum (First Full Moon): 15th day of the 1st lunar month
- Dano: 5th day of the 5th lunar month
- Chuseok (Harvest Festival): 15th day of the 8th lunar month