Born in Whanganui in 1927, Hickman grew up in rural Northland until his family moved to Auckland in 1941.
After finishing his secondary education there, he completed a building apprenticeship and at the same time studied mathematics, physics and geology part-time.
[1] He then moved to Dunedin, and studied at the University of Otago,[1] from where he graduated with a Bachelor of Science in 1951.
He served as vice-president of Regional Association V of the World Meteorological Organization from 1982 to 1986, and president from 1986 to 1988.
[1] Hickman also served as the convenor of the climate committee of the Royal Society of New Zealand until 1994.