The number of days between two adjacent solar terms is about 15 days, but why can the longest number of days between summer solstice and slight summer heat reach 17 days?

In fact, solar terms should be accurate not only to the sky, but also to the hours and minutes.

365÷24= 15.2 1 (day), and the average solar term is 15.2 1 day, so if it is the night from summer to Sunday, it is possible to enter a slight summer heat in the early morning. From the calendar, the difference between them is 17 days, but the actual time is still the same.

In addition, because the earth's orbit around the sun is elliptical, in the northern hemisphere in summer, the earth is far from the sun and rotates slowly, so it takes a long time to sweep the orbit with the same arc.