CA Educ Code Section 37201

(a)

A school month is 20 days or four weeks of five days each, including legal holidays but excluding weekend makeup classes. For the purposes of counting attendance only in providing for a school calendar the winter vacation period, or any portion thereof, may be excluded by the school district in the definition of a school month.

(b)

The provisions of subdivision (a) of this section are limited to defining a school month for attendance-counting purposes only.