Okla. Stat. tit. 75 § 250.8
In computing any period of time prescribed or allowed by the Administrative Procedures Act, the day of the act, or event, from which the designated period of time begins to run shall not be included. The last day of the period so computed shall be included, unless it is a Saturday, a Sunday, or a legal holiday as defined by the Oklahoma Statutes or any other day when the receiving office does not remain open for public business until 4:00 p.m., in which event the period runs until the end of the next day which is not a Saturday, a Sunday, or a legal holiday as defined by the Oklahoma Statutes, or any other day when the receiving office does not remain open for public business until 4:00 p.m.; provided, permanent rules shall become effective on the tenth day after the rules are published in "The Oklahoma Register", as set forth in subsection B of Section 304 of this title, regardless of the day of the week.
Okla. Stat. tit. 75, § 250.8