A school day for grades K-12 may be counted as a day in session when the school is open and the students are under the guidance and direction of teachers in the teaching process for not less than four (4) hours of instruction per day. Lunch periods, breaks, passing time, and recess are not included in the four (4) hours.
A half-day in session in grades K-12 occurs when either the students are under the guidance and direction of teachers in the teaching process for a minimum of two and one-half (2 ½) hours of instruction; or when teachers are involved in staff development activities for a minimum of two and one-half (2 ½) hours per day. If a day has less than two and one-half (2 ½) hours of instruction, that day is reported as a vacation day.
The minimum number of instructional hours may be reduced up to eleven (11) hours for kindergarten and twenty-two (22) hours for grades 1-12 for staff development activities. [Idaho Code 33-512 & State Board of Education Rule 08.02.01.250]