Date of birth I think you will find that JKR has not included years on any of the birthdates infact I think you will find there are no years included in any of the books The dates that people give are derived assuming that the first Harry potter book happened the year it was published This however is never stated in the books or in any interviews In the most recent book the Prime Minister of the UK makes an apperance but is never physically described or called by name This lends evidence to the idea that the books are not set in a specific time