Why do the dates of Ramadan change each year?
The exact dates of Ramadan change every year because Islam uses a lunar calendar, which means that each month begins with the sighting of a new moon. Because lunar months are shorter than the solar months used elsewhere, Islamic holidays begin on different days each year. The start of Ramadan comes around 11 days earlier each year according to the western Gregorian calendar, and consequently is not associated with any particular western month. For Muslims living in Britain, the fast may therefore be comparatively short if Ramadan falls during the winter months, or much longer if it occurs during the summer.
