[6] Tempest was educated at Stonyhurst College,[7] where he won distinction in mathematics, then spent three years[6] training for the merchant service at HMS Worcester.
[8] He worked as a mining engineer, and spent a few months as a sugar farmer in South Africa,[6] before moving to Canada in 1911 with his brother Edmund to farm in Perdue, Saskatchewan, but they returned to England to enlist[7] in October 1914.
[10] His battalion was sent to France in May 1915,[6] where he saw action during the Second Battle of Ypres in April,[9] which marked the first large-scale use by the Germans of chlorine gas on the Western Front.
[13] At 23:45 on 1 October 1916, Tempest was on patrol about 15,000 ft (4,600 m) over South-West London flying B.E.2c night fighter, serial number "4557", having taken off from North Weald around 22:00.
Meanwhile, Zeppelin L.31, commanded by Kapitänleutnant Heinrich Mathy had flown across the North Sea, and crossed the English coast at Lowestoft, but was unable to penetrate London's defences, coming under heavy anti-aircraft fire.
[15] The next day he travelled to Potters Bar to survey the wreck of L.31, but the area was cordoned off by the Army, and he was obliged to pay a shilling to see the wreckage from an adjoining farm.
[14] Two weeks later, on 13 October Tempest was made a companion of the Distinguished Service Order, "...in recognition of conspicuous gallantry and devotion to duty in connection with the destruction of an Enemy Airship.
That summer the squadron saw action during the battles of Vimy Ridge, Arras, Messines, and third Ypres, gaining a reputation for energy and efficiency,[19] while on 27 June Tempest was appointed a flight commander with the temporary rank of captain.
[22] His citation, gazetted on 5 March 1918, read: The same month his squadron become part of the Independent Air Force, and was relocated to Ochey aerodrome to fly strategic bombing missions over Germany, attacking munitions factories in the Rhine towns.
100 Squadron was temporarily moved to an aerodrome near Rheims, flying tactical missions against German lines of communication, before returning to Ochey and the Independent Air Force.
[29] In May 1919 Tempest became engaged to Camille Millicent Best, of Brussels,[30] but eventually married Ethel Fernandes on 5 April 1923 at All Saints' Church, Ennismore Gardens, London.