What do you mean by rain below 19 on the calendar?

Rain is the second of the 24 solar terms. On the fifteenth day of the first month of each year (February 18-20 in Gregorian calendar), when the longitude of the sun reaches 330 degrees, this rain is the rain of 24 solar terms. At this time, the temperature rises, the snow melts and the precipitation increases, hence the name rain. Generally, the rainy and rainy solar term begins on February 18 or 19 of Gregorian calendar and ends on March 4 or 5. Rain, like Grain Rain, light snow and heavy snow, is a solar term reflecting precipitation.