Minor Heat, comes between July 6th and 8th annually, is one of the 24 solar terms in the Chinese lunar calendar. By then, the sun is located at the 105 degree of the celestial longitude. Yue Ling 72 Hou Ji Jie, a book pertaining to the interpretation of moon, says: “June can be divided into big and small in terms of heat, it is small at the beginning of one month and big in the middle of one month. It is especially small on the day of Minor Heat.” The ancient people thought that it was not the hottest time during the Minor Heat period and then named it the Minor Heat. There is also a song with the lyrics “the Minor Heat is not hot but the Major Heat.” which means that the hottest period is coming but the extremely hot point has not arrived yet. Dog days usually appears on the 28th day after the Summer Solstice in China.

The date of Minor Heat calculation: [Y*D+C]-L

Formula explanation: Y= the last two digit of the year, D=0.2422, L=the number of leap year, 21 Century=7.108, 20 Century=7.928.

For example: the date of Minor Heat in 2088= [88×0.2422+7.108]-[88/4]=28-22=6, so the Minor Heat falls on June 6th.

Exception: 1925 and 2016, add one to the calculated result