May 5 or May 6 every year is the beginning of summer in the lunar calendar. "The bucket points to the southeast, and the dimension is the beginning of summer. All things grow up here, so it is called the beginning of summer." At this time, the sun's ecliptic longitude is 45 degrees. In astronomy, the beginning of summer means bidding farewell to spring and is the beginning of summer. People traditionally regard the Beginning of Summer as an important solar term when the temperature rises significantly, the heat is approaching, thunderstorms increase, and crops enter the peak season.