Respite care is a much broader category than adult day care. It basically encompasses any form of care provided on a temporary basis, typically to relieve a family member who is acting as the regular care giver. To this extent, adult day care itself is arguably a form of respite care.
However, many other facilities, such as Slim Haven, an Adult Foster Care home, and nursing homes provide respite care. The scope of services provided will generally be proportionate to the facility where you receive the services.
For instance, a nursing home is capable of providing more advanced healthcare services than an Adult Foster Care home or an adult day care. Some home health agencies also provide respite care in the form of temporary nurses or home health aids while your caregiver is unavailable.
All of these facilities other than adult day care can generally provide the respite care 24 hours per day if necessary on a short-term basis usually lasting either a few days or even a few weeks.