Abstract: The population of any area at any one time includes persons who usually reside there but also others who do not have their permanent residence there but work, recreate, visit, go to school or undertake other activities there. Standard data only captures the usual residents of places whereas the actual numbers in a place can vary greatly according to whether it is day or night, weekday or weekend, summer or winter etc. These temporary populations have a relatively greater impact in non-metropolitan than in metropolitan Australia and are a neglected but important element in regional population dynamics. This policy brief examines some of the patterns and implications of this mobility.