Are the 24 solar terms fixed? How to calculate the fright?

The spring rain shakes the spring and the valley days, and the summer is full of mountains and summers.

Autumn dew, autumn frost, little snow in winter and cold in winter.

This is twenty-four solar term song. The first half of the year is on the 6th, 2 1, and the second half is on the 8th and 23rd, with a difference of 1 ~ 2 days.

So the date of the solar term is not fixed, but it is more accurate according to the Gregorian calendar 1993.