This raised the issue of whether or not the priority period expired on August 15, 2009 or was extended to August 17, 2009 because August 15, 2009 was a Saturday.  PCT Rules 2.4 and 80.5 govern this situation and state as follows:

Rule 2.4 – “Priority Period”

(a) Whenever the term “priority period” is used in relation to a priority claim, it shall be construed as meaning the period of 12 months from the filing date of the earlier application whose priority is so claimed. The day of filing of the earlier application shall not be included in that period; and

(b) Rule 80.5 shall apply mutatis mutandis to the priority period; and

Rule 80.5 – “Expiration on a Non-Working Day or Official Holiday”

If the expiration of any period during which any document or fee must reach a national   Office or intergovernmental organization falls on a day:

  (i)  on which such Office or organization is not open to the public for the purposes of the transaction of official business;

the period shall expire on the next subsequent day on which none of the said four circumstances exists.

The U.S. Patent Office’s normal operation of business days are Monday through Friday. 

- John Thomas