As a result of the federal government’s sequester (budgetary constraints), the IRS will be closed on May 24, June 14, July 5, July 22, and August 30. This means that all of its toll-free hotlines and offices will be closed on these days when IRS workers will be furloughed.
If you need to contact the IRS about a particular action, such as making your second estimated tax payment for 2013 (which is due on June 17), be sure to take the IRS closures into account. The closures do not extend the time for taxpayer action.
Source: IR-2013-51
A 12-month period ending on the last day of any month other than December. Partnerships, S corporations, and personal service corporations are limited in their choice of fiscal years and face special restrictions.