M.W.C. Hepworth served in the (British) Indian Marine, mainly in the mercantile marine, but also in the Royal Navy. After retiring from the Royal Navy as a Commander he was appointed marine superintendent of the Meteorological Office, London, in 1899 and was an expert assessor to the International Conference on Safety of Life at Sea in 1913. He became a member of the British Association for the Advancement of Science in 1904 and was honoured as a Companion of the Order of the Bath (CB).
Hepworth was a Fellow of the (British) Meteorological Society and published actively on meteorology at sea. One of his earlier papers that pertains to southern Africa, "Weather forecast and storm warnings on the coast of South Africa, with remarks upon steam navigation between Table Bay and Natal", appeared in the Quarterly Journal of the Meteorological Society in 1883. It was also published in the form of a pamphlet (London, 1885), and included in the General directory and guide-book to the Cape of Good Hope and its dependencies for 1884 to 1886. Based at least partly on his own experience in these waters, it dealt with the weather, climate and ocean currents of the region throughout the year, particularly with storms and their relation to atmospheric pressure and conditions at the various ports. Another of his papers, "Wind systems and trade routes between the Cape of Good Hope and Australia", was published in the same journal in 1891. Both these papers were included in his later book, Notes on maritime meteorology... (1907). Ten years later he published The relation between pressure, temperature and air circulation over the South Atlantic Ocean (London, 1917).
Other works by Hepworth were: Current observations on the Canadian-Australian route (Sydney, 1898, The effect of the Labrador current upon the surface temperature of the North Atlantic... (London, 1912), and several reports and papers published by the Meteorological Office of Great Britain.