According to the solar terms of the lunar calendar
Twenty-four solar terms are divided into twenty-four seasons and climates that reflect the natural phenomena and agricultural characteristics in a certain area of China (represented by the middle and lower reaches of the Yellow River) according to the position of the sun returning to the ecliptic (the route that the sun "walks" through the earth in one year).
The 24 solar terms are calculated according to the lunar calendar. If you simply understand it, you can also understand it according to the solar calendar (western calendar). The days are fixed, but there may be a difference of one or two days every year due to leap months.
In the lunar calendar, the moon orbits the earth 1 month, but a leap month is set, which is consistent with the periodic movement of the moon and the earth around the sun. The "month" in the western calendar has nothing to do with the month.