Have you set the date of the summer solstice?
Summer solstice is the earliest of the 24 solar terms, also known as "summer solstice" and "summer solstice festival". In the seventh century BC, the summer solstice was determined by measuring the sun shadow with civil soil rules;
During the summer solstice, the sun reaches the northernmost part of the year, and the days in the northern hemisphere are the longest. The farther north, the longer the days. This is the biggest day of the year when the sun illuminates the northern hemisphere, and it is also the highest day from the earth.
Like the winter solstice, the summer solstice is also a solar term reflecting the changes of the four seasons. Astronomy stipulates that the summer solstice is the beginning of summer in the northern hemisphere. The temperature will continue to rise after the summer solstice. There is a saying that summer solstice is not too hot.
Summary:
The exact date of the summer solstice has not yet been determined. It is a day in the middle of June 20th, 2 1 or 22nd of the Gregorian calendar every year. It is the tenth solar term in the twenty-four solar terms of the lunar calendar, and the fourth solar term when the sun reaches 90 degrees of the Yellow Meridian in summer.