Is Laylat al-Qadr one single night, or does it vary according to the time zones of different countries, such that the odd-numbered night to which the Prophet, peace and blessings be upon him, referred does not coincide [globally]?

The divergence in the sighting of Arabic months is a matter of both religious law (shar‘an) and divine decree (qadran). Consequently, each sighting point has its own specific Night of Decree (Laylat al-Qadr). Others may share in it, and it may continue for the people of another sighting point until dawn. It is known that Laylat al-Qadr can last for 24 hours across the entire earth, and each sighting point has its own specific duration of night.