When does Pitru Paksha occur each year?

Pitru Paksha falls in the second fortnight (Krishna Paksha) of the Hindu lunar month of Bhadrapada, usually corresponding to September or October in the Gregorian calendar. It begins on the Purnima (full moon day) or the day after Purnima and ends on the Amavasya (new moon day), known as Sarva Pitri Amavasya or Mahalaya Amavasya. (For current year dates, a specific search is needed closer to the time.)