Schema.org has several mechanisms related to opening / closing hours; these have expressivity gaps and other inclarities. Let's collect those here, with details in other related bugs if needed.

Brief overview:

Opening Hours

1. http://schema.org/openingHours the informal domain-specific language for common cases
2. http://schema.org/openingHoursSpecification (a property) + http://schema.org/OpeningHoursSpecification (a type, expected value of the property).

There is also the Event type. Although there was an earlier proposal, currently each event is described individually (i.e. there is no framework for repeated events). http://schema.org/Event says,

"An event happening at a certain time and location, such as a concert, lecture, or festival. Ticketing information may be added via the 'offers' property. Repeated events may be structured as separate Event objects."

Interactions? Should 'openingHours' be qualified with 'typical, usual', so that it can be over-ridden? Do we have a convention for treating all opening hours given in the same document/page/graph as together providing an overview of opening times? How can exceptions be recorded? How can closed-all-day situations be represented? Does the micro-language for openingHours tolerate a mix of case (mo vs MO)? Are 3-letter day codes acceptable? (Mon/MON/mon, ...).

See also: Museum-related notes, https://docs.google.com/a/danbri.org/document/d/1at0hgbzZIYDppgGudm0EHSV6vpc6OIv_YDAiydWg6aw/edit