Is the summer of solstice summer?

According to the saying of all seasons, summer comes in April and May every year, but we all know that the weather at this time has not really reached the hot degree of summer that we are familiar with, and the definition of summer solstice is the arrival of hot summer in the 24 solar terms. So can we think that the summer solstice means the arrival of summer?

One of the 24 solar terms from the summer solstice. Gregorian calendar June 2 1 day or 22. On this day, the northern hemisphere has the longest day and the shortest night; The southern hemisphere is the opposite. To, refers to Yang, from the beginning to the north of the extreme and heaven. "Zhou Li Chun Guan von Shi Xiang" Han Zhengxuan Note: "Summer solstice, the sun is in Tokyo, and the scenery is five inches." "Yi Zhou Shu Shi Xun": "On the day of the summer solstice, the antlers are untied; On the fifth day, it began to ring. " In the Southern Dynasties, Liang Zonggu wrote the Chronicle of Jingchu: "Summer Solstice Festival."

Calendar, including the concept of 24 solar terms, is related to astronomy. Summer solstice is the first solar term measured by the ancients, and the method is to observe the sun shadow with soil gauge. According to "Zunxian Manuscript", "The day reaches the north, the day is long [refers to the sunshine time], and the sun shadow is short, so it is called the summer solstice. At best, it is excellent. " Obviously, the summer solstice is the limit of summer, and the winter solstice is the limit of winter. So far, Long Summer and beginning of winter are the beginning of summer and winter.

Moreover, the summer solstice, the winter solstice and even all the 24 solar terms are not a day, but an accurate time. Looking up astronomical legislation, we can know that the summer solstice in a certain year is a certain day, hour, minute and second. The summer solstice is the shortest moment of the sun shadow.

However, this does not mean that the summer solstice is the hottest and the winter solstice is the coldest, because it only refers to the astronomical sense, that is, during the summer solstice, the direct point of the sun is the northernmost, while the winter solstice is the opposite. It takes a certain process for the surface to absorb heat and reflect it into the atmosphere to raise the temperature. Generally speaking, it is hottest from summer to the next 20-30 days. Similarly, the solstice is the coldest 20-30 days after winter. However, the solar radiation angle is different from north to south, and the specific heat of different land surfaces, including the sea surface, is also different, so the expansion and contraction of near-surface air are also different, forming air masses and air pressures with different forces. If affected by the movement of air mass, the heat and cold are variable.