Wheal was born in Durban, South Africa, on 28 August 1996 to a Scottish mother. He attended Clifton School in Durban, where he matriculated in December 2014. He began his cricketing career with the Kwazulu-Natal youth teams, where he played up to under-19 level. He also represented the province in youth field hockey. While playing under-19 cricket, he was spotted by Hampshire coach Dale Benkenstein, who is also an assistant coach with the Dolphins in Durban.

Wheal impressed Benkestein and was offered a development contract with Hampshire for the 2015 season due to a shortage of fast bowlers at the county, with only Chris Wood and Tom Barber as available backups to the first team side.

Wheal impressed greatly in pre-season, performing well in games on the tour of Barbados and in a friendly against Kent. A strong performance then against Middlesex 2nd XI for Hampshire's 2nd XI where he took 10 wickets in the match and earned himself a call up to the first team for the match against Middlesex on 17 May 2015. Hampshire batted first in this match where Wheal batted at number 10 finishing 3 not out. In Middlesex's 1st innings Wheal took the wicket of opener Sam Robson for 10 runs by bowling him out. He finished with figures of 1/97 from his 20 overs as Middlesex where bowled out for 362. The match, which was rain affected, would end in a draw.

Wheal hold a British passport through his parentage. After joining Hampshire, he expressed an interest in representing England upon fulfilling the residential qualifications.

Wheal is qualified to represent Scotland through his mother. In August 2015 he played for a Scotland XI against MCC at Titwood, Glasgow, taking seven wickets. He was subsequently fast-tracked to selection for the full Scotland team, and in December 2015 was named in the squad for the tour of Hong Kong, that took place the following month.^[4][5]