The Chinese Calendar

This section describes The Chinese Calendar, which is a lunisolar calendar based on the tropical year and the synodic month.

The Chinese calendar is a lunisolar calendar, which is based on the tropical year and the synodic month.

The primary cycle in the Chinese calendar is the Chinese month, which is closely synchronized to the synodic month. Since the synodic month has an average of about 29.5305888531 days, the number of days in a Chinese month varies between 29 days and 30 days from month to month.

The first day of a Chinese month must be the new moon day, when the moon is completely dark, that is the moon is in conjunction with the sun.

The secondary cycle in the Chinese calendar is the solar term system, which is closely synchronized to the tropical year. The solar term system has 12 principal terms to indicate the sun's longitudes at every 30 degrees, with the first principle term defined as the day when the sun's longitude at 330 degrees.

In addition to the 12 principal terms, 12 sectional terms are added to break the sun's longitude into 24 15-degree segments. The following table lists the 24 solar terms and their approximate dates in Gregorian calendar.

Term   Long.   Greg.    Dur.   Ch. Name      En. Name

S. 1   315     Feb. 4          Lichun        Beginning of Spring
P. 1   330     Feb.19   29.8   Yushui        Rain Water
S. 2   345     Mar. 6          Jingzhi       Waking of Insects
P. 2     0     Mar.21   30.2   Chunfen       Spring Equinox
S. 3    15     Apr. 5          Qingming      Pure Brightness
P. 3    30     Apr.20   30.7   Guyu          Grain Rain
S. 4    45     May  6          Lixia         Beginning of Summer
P. 4    60     May 21   31.2   Xiaoman       Grain Full
S. 5    75     Jun. 6          Mangzhong     Grain in Ear
P. 5    90     Jun.22   31.4   Xiazhi        Summer Solstice
S. 6   105     Jul. 7          Xiaoshu       Slight Heat
P. 6   120     Jul.23   31.4   Dashu         Great Heat
S. 7   135     Aug. 8          Liqiu         Beginning of Autumn
P. 7   150     Aug.23   31.1   Chushu        Limit of Heat
S. 8   165     Sep. 8          Bailu         White Dew
P. 8   180     Sep.23   30.7   Qiufen        Autumnal Equinox
S. 9   195     Oct. 8          Hanlu         Cold Dew
P. 9   210     Oct.24   30.1   Shuangjiang   Descent of Frost
S.10   225     Nov. 8          Lidong        Beginning of Winter
P.10   240     Nov.22   29.7   Xiaoxue       Slight Snow
S.11   255     Dec. 7          Daxue         Great Snow
P.11   270     Dec.22   29.5   Dongzhi       Winter Solstice
S.12   285     Jan. 6          Xiaohan       Slight Cold
P.12   300     Jan.20   29.5   Dahan         Great Cold

The third cycle in the Chinese calendar is the Chinese year, which is closely synchronized to the tropical year. A common Chinese year has 12 Chinese months, with 353, 354, or 355 days. which is about 11 days less than a tropical year. In order to bring the Chinese year cycle in line with the tropical year cycle, a leap year is defined after about every 3 common years. A leap year has 13 months, with the extra month called leap month.

To determine which year is a leap year and after which month to add the leap month, the Chinese calendar uses the following leap year rules:

Chinese years are counted in 60-year cycles. Each year is named with a combination of one of the 10 heavenly stems (tiangan) and one of the 12 earthly branches (dizhi) sequentially, and repeatedly. 10 heavenly stems are mapped to 5 elements as Wood, Wood, Fire, Fire, Earth, Earth, Metal, Metal, Water, and Water. 12 earthly branches are also mapped to 12 animals as Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Chicken, Dog, and Pig.

It is believed that the Chinese calendar has completed 78 cycles so far. This year, 1999 in Gregorian calendar, is the 16th year in the 79th cycle, or year 4696. Note that January 1, 1999 was still in year 4695, because the Chinese year is about one month behind.

The Chinese calendar rules can be summarized as:

Table of Contents

 About This Book

Chinese Calendar Background Information

 Astronomical Bases of Calendars

 The Gregorian Calendar

The Chinese Calendar

 Chinese Calendar Algorithm and Program

 Chinese Calendars: Year 1901 to 1910

 Chinese Calendars: Year 1911 to 1920

 Chinese Calendars: Year 1921 to 1930

 Chinese Calendars: Year 1931 to 1940

 Chinese Calendars: Year 1941 to 1950

 Chinese Calendars: Year 1951 to 1960

 Chinese Calendars: Year 1961 to 1970

 Chinese Calendars: Year 1971 to 1980

 Chinese Calendars: Year 1981 to 1990

 Chinese Calendars: Year 1991 to 2000

 Chinese Calendars: Year 2001 to 2010

 Chinese Calendars: Year 2011 to 2020

 Chinese Calendars: Year 2021 to 2030

 Chinese Calendars: Year 2031 to 2040

 Chinese Calendars: Year 2041 to 2050

 Chinese Calendars: Year 2051 to 2060

 Chinese Calendars: Year 2061 to 2070

 Chinese Calendars: Year 2071 to 2080

 Chinese Calendars: Year 2081 to 2090

 Chinese Calendars: Year 2091 to 2100


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