Winter solstice instant of the solstice can be calculated, direct observation of the solstice by amateurs is impossible because the sun moves too slowly or appears to stand still (the meaning of "solstice"). However, by use of astronomical data tracking, the precise timing of its occurrence is now public knowledge. One cannot directly detect the precise instant of the solstice (by definition, one cannot observe that an object has stopped moving until one later observes that it has not moved further from the preceding spot, or that it has moved in the opposite direction). Further, to be precise to a single day,
Chinese calendar the winter solstice, in a solar year. The 11 mid-climates, except for the winter solstice, are in the 11 or 12 complete months. The complete months are numbered from 0 to 10, and the incomplete months are considered the 11th month. The first month without a mid-climate is the leap, or intercalary, month. Leap months are numbered with "rùn" , the character for "intercalary", plus the name of the month they follow. In 2017, the intercalary month after month six was called "Rùn Liùyuè", or "intercalary sixth month" () and written as "6i" or "6+". The next intercalary month (in