2011 ORS § 419B.854¹
Computing statutory time periods

(1) In computing any period of time prescribed or allowed by any applicable statute, by the local rules of any court or by order of court, the day of the act or event from which the designated period of time begins to run is not included. The last day of the period so computed is included, unless it is a Saturday or legal holiday, in which event the period runs until the end of the next day that is not a Saturday or a legal holiday. If the period of time relates to serving a public officer or filing a document at a public office and if the last day falls on a day when that particular office is closed before the end of or for all of the normal work day, the last day is excluded in computing the period of time, in which event the period runs until the close of office hours on the next day the office is open for business. When the period of time prescribed or allowed, without including the extra time allowed by subsection (2) of this section, is less than seven days, intermediate Saturdays and legal holidays are excluded in the computation. As used in this subsection, a legal holiday means a day described in ORS 187.010 (Legal holidays) or 187.020 (Additional legal holidays).

(2) Except for service of summons, whenever a party has the right or is required to do some act within a prescribed period after the service of a notice or other paper upon the party and the notice or paper is served by mail, three days are added to the prescribed period. [2001 c.622 §16]