Okla. Stat. tit. 36 § 121
In computing any period of time prescribed or allowed by this title, by the rules of the Insurance Commissioner, or by any applicable statute, the day of the act, event or default 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, a legal holiday as defined by the Oklahoma Statutes or any day when the office of the Commissioner 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 when the office of the Commissioner is open until 4:00 p.m. When the period of time prescribed or allowed is less than seven (7) days, intermediate Saturdays, Sundays and legal holidays shall be excluded in the computation.
Okla. Stat. tit. 36, § 121