Dowding was born at St. Ninian's Boys' Preparatory School in Moffat, Dumfriesshire, the son of Arthur John Caswall Dowding and Maud Caroline Dowding (née Tremenheere). His father had taught at Fettes College in Edinburgh before moving to Moffat.[1] Dowding was educated at St Ninian's School and Winchester College.[2] He trained at the Royal Military Academy, Woolwich before being commissioned as a second lieutenant in the Royal Garrison Artillery on 18 August 1900.[3]