Why are 384 days in the 2020 Chinese Rat Year?
- Saturday, 04/04/2020, April 4, 2020
- Saturday, 06/06/2020, June 6, 2020
- Saturday, 08/08/2020, August 8, 2020
- Saturday, 10/10/2020, October 10, 2020
- Saturday, 12/12/2020, December 12, 2020
2020 is the Chinese year of the Rat. Chinese New Year Day of 2020 is on January 25, 2020. Chinese New Year Day of 2021 is on February 12, 2021. That means the Chinese lunar year of the Rat year has 384 days in 2020.
How come has 2020 Chinese lunar year 384 days? That's because the Chinese lunar year of 2020 has a leap lunar month (Intercalary Month). 2020 Chinese lunar calendar has two 4th lunar months. The second 4th lunar month from May 23, 2020 to June 21, 2020 is the leap month, which has 30 days. A lunar month is about 29.53 days. 12 lunar months have 354.36 days. 2020 lunar year is around 354+30=384 days.
Why does Chinese Lunar Calendar need leap Months?
Chinese Lunar Calendar combines two counting systems, the cycles of the sun and moon. The starting point should be the time which Sun and Moon are in the same tropical position in the sky. Therefore, that's a new moon day. The Winter Solstice is the starting day of a solar year. The new moon time at midnight of the Winter Solstice is the beginning time of the Chinese Lunar Calendar cycle sounds perfect. (see the first day of Chinese Lunar Calendar Cycle at Chinese Calendar Reform History) But that's too complicated. Here we just want to consider a smaller cycle, the Sun and Moon on the same position in the sky.
The length of a year on Earth is about 365.2425 days. A new moon to another new moon takes about 29.53 days. 12 lunar months takes 29.53 X 12 = 354.36 days. The cycle of Moon is off the cycle of Sun 11 days a year. It will be off 33 days after three years. Therefore, it is required an extra lunar month before the cycle of the third year.
One year is about 365.2425 days and one lunar cycle is about 29.53 days. Therefore, one year has about 12.3685 lunar months. 12.3685 is about 12 and 7/19. That means we need seven extra lunar months in 19 years to put sun and moon back to the same sky position. The next Chinese Lunar leap month is in 2023, the year of Rabbit. That is a leap second lunar month, from March 22, 2023 to April 19, 2023 in China timezone.
How to determine a Chinese Lunar leap Month?
We need to know the Chinese zodiac month before understanding the lunar leap month. The Chinese calendar divides the year into 12 segments according to the sun's positions on the tropical zodiac. The beginning of a solar month is called the Segment Point. The first solar month, Tiger month, begins when the sun enters the 315th degree on the tropical zodiac. These are the 12 Chinese zodiac months. The middle of a solar zodiac month is called the Center Point. 12 Center points are the same as the 12 western zodiac signs.
The name of the lunar month is derived from the Solar Center Point. For example, If a lunar month contains the Center Point of Rain Water (Pisces), then That's the Tiger month. If a lunar month does not contain any Solar Center Point, that month is known as a Leap Month. For example, the lunar month contains the Center Point of Grain Fills (Gemini) is the 4th lunar month, which is the Snake Month. The lunar month contains the Center Point of Summer solstice (Cancer) is the 5th lunar month, which is the Horse Month. In China timezone, Grain Fills is on 5/20/2020 at 21:49 and Summer Solstice is on 6/21/2020 at 5:45.
|2020 Lunar Months of Timezone 8 (China)|
|Lunar Month||Starting Date||Ending Date||Center Point|
|4||April 23, 2020||May 22, 2020||May 20, 2020|
|Leap 4||May 23, 2020||June 20, 2020|
|5||June 21, 2020||July 20, 2020||June 21, 2020|
The lunar month form May 23, 2020 to June 20, 2020 doesn't have any Center Point. It should be assigned as a leap month. The name of the lunar month uses the previous one. Therefore, it's leap 4th month.
Does the Chinese Lunar Calendar of 2020 contain two Snake Months?
There are two 4th lunar months in 2020. The 4th lunar month corresponds with the zodiac Snake month. Can we say we have two Snake months in 2020? The answer is no. The counting system of zodiac month is not from the lunar calendar. The zodiac months are from the Segment Points, which is a solar system. The names of the zodiac months are from the Stem-Branch system. The Snake month of 2020 is from 5/20/2020 to 6/20/2020.
The lunar year of 2020 is from January 25, 2020 to February 11, 2021. The Tiger month is from 2/4/2020 to 3/4/2020. The next Tiger month is from 2/3/2021 to 3/5/2021. The starting date of the Tiger month is the Start of Spring. We can say that the lunar year of 2020 contains two Start of Spring points and spans over two Tiger months.