Okla. Stat. tit. 70, § 1-110
A school month shall consist of twenty (20) school days during which school is actually taught or school activities performed. Provided, that holidays, elections, days devoted to professional meetings and other days when school is closed may be included in the number of days required for a regular school month, but no holiday or other occasion when school is not in session shall be included in the one hundred eighty (180) days required to be taught, except not to exceed five (5) days may be used for attendance of professional meetings. Any district may pay teachers and other employees on the basis of calendar months for twelve (12) months, as elsewhere provided by the Oklahoma School Code.
Laws 1971, HB 235, 1155, c. 281, § 1-110, emerg. eff. July 2, 1971.