29 CFR § 778.218 - Pay for certain idle hours.
(a) General rules. Payments which are made for occasional periods when the employee is not at work due to vacation, holiday, illness, failure of the employer to provide sufficient work, or other similar cause, where the payments are in amounts approximately equivalent to the employee's normal earnings for a similar period of time, are not made as compensation for his hours of employment. Therefore, such payments may be excluded from the regular rate of pay under section 7(e)(2) of the Act and, for the same reason, no part of such payments may be credited toward overtime compensation due under the Act.
(b) Limitations on exclusion. The provision of section 7(e)(2) of the Act deals with the type of absences which are infrequent or sporadic or unpredictable. It has no relation to regular “absences” such as regularly scheduled days of rest. Sundays may not be workdays in a particular establishment, but this does not make them either “holidays” or “vacations,” or days on which the employee is absent because of the failure of the employer to provide sufficient work. The term holiday is read in its ordinary usage to refer to those days customarily observed in the community in celebration of some historical or religious occasion; it does not refer to days of rest given to employees in lieu of or as an addition to compensation for working on other days.
(c) Failure to provide work. The term “failure of the employer to provide sufficient work” is intended to refer to occasional, sporadically recurring situations where the employee would normally be working but for such a factor as machinery breakdown, failure of expected supplies to arrive, weather conditions affecting the ability of the employee to perform the work and similarly unpredictable obstacles beyond the control of the employer. The term does not include reduction in work schedule (as discussed in §§ 778.321 through 778.329), ordinary temporary layoff situations, or any type of routine, recurrent absence of the employee.
(d) Other similar cause. The term “other similar cause” refers to payments made for periods of absence due to factors like holidays, vacations, sickness, and failure of the employer to provide work. Examples of “similar causes” are absences due to jury service, reporting to a draft board, attending a funeral, inability to reach the workplace because of weather conditions, attending adoption or child custody hearings, attending school activities, donating organs or blood, voting, volunteering as a first responder, military leave, family medical leave, and nonroutine paid leave required under state or local laws. Only absences of a non-routine character which are infrequent or sporadic or unpredictable are included in the “other similar cause” category.