John R. Sutton was educated at the University of Cambridge, where he qualified as Bachelor of Arts (BA). He appears to have been awarded the degree Master of Arts there later, because from about 1900 the designation MA regularly appears behind his name. He had an early interest in astronomy, publishing his first paper, on "Comet systems", in the Journal of Science and Annals of Astronmy (1885). In 1889 he was appointed by De Beers Consolidated Mines, Ltd. as a clerk at the Kimberley diamond mine. A few years later he was asked to establish a meteorological observatory at Kenilworth, a township of De Beers just outside Kimberley. Funds appear to have been readily available, as Sutton equiped the observatory with a wide variety of instruments. There was a standard mercury barometer with a fixed cistern and an adjustable zero point, a Fortin barometer with an adjustable cistern and a fixed zero point, and a photo-barograph which made a photographic record of the height of a mercury barometer. Hourly readings of wet and dry bulb thermometers were made with a device called a reversing thermometer, designed to measure sea temperatures at various depths, which Sutton claimed to have adapted for the first time to measure air temperatures. There were twelve of these devices which reversed hourly, controlled by clockwork and electricity. Other instruments included anemometers, rain gauges, evaporation tanks, radiometers, seismographs, and a 110 mm equatorially mounted telescope with various accessories. In addition to the main observatory Sutton set up nine rainfall stations in the district. Observations were started in 1893.
From 1898 to 1903 Sutton provided a copy of his results to the Meteorological Commission of the Cape of Good Hope, which published summaries in its annual reports. He was commended in particular for continuing his observations throughout the siege of Kimberley in 1899, at the beginning of the Anglo-Boer War (1899-1902). Following the international classification adopted by the International Meteorological Congress in 1873 (introduced by the commission in 1897), the Kenilworth observatory was classified as the only first-order meteorological station from which returns were received. It was in fact the first, and for years the only, first-order station in southern Africa, and probably in all of Africa. (At this time the meteorological station at the Royal Observatory in Cape Town was classified as a "subsidiary first-order station".)
Over a period of three decades Sutton made many and important contributions to the development of physical meteorology in southern Africa. He was a devoted and painstaking observer, aware of observational difficulties and the need to reduce and interpret his observations. He wrote about 70 papers on a variety of meteorological subjects, in a rather wordy style. Most of these were published in the Transactions of the South African Philosophical Society (SAPS), the Transactions of the Royal Society of South Africa (RSSA) and the Reports of the South African Association for the Advancement of Science (SAAAS). One of his early papers addressed the problem of determining true daily values of temperature, pressure and humidity from observations taken at different places and at various times. This important contribution to the standardisation of observations appeared in 1903 (SAAAS, pp. 119-143). Initially his publications were based mainly on his observations at Kimberley, but as data from other observers became more readily available he started studying the meteorology of the inland plateau of southern Africa. He collected and interpreted climatological data for a large part of the sub-continent, though he sometimes complained about the poor quality of the observations. In "Some pressure and temperature results for the great plateau" (SAPS, 1902, Vol. 11, pp. 243-318), in which he compared the results for Kimberley with those for Durban, he considered the possibility of compiling a synoptic chart reduced to, for example, 4000 feet, rather than sea-level. This later became common practice. In "An introduction to the study of South African rainfall" (SAPS, 1904, Vol. 15, pp. 1-28) he related the rainfall data for Kimberley to those for the rest of the country, discussed the atmospheric circulation associated with summer rainfall in he interior, and drew attention to the importance of diurnal variations of wind in this respect. Other publications on rainfall in South Africa followed in later years.
He also studied "The diurnal variation of barometric pressure" and its causes, using data for Kimberley and Dar es Salaam (SAAAS, 1905/6, pp. 13-48). At first he used his observations to detect the possible effect of variations in vapour tension on the pressure cycle (Quarterly Journal of the Royal Meteorological Society, 1904). A few years later he and Elizabeth M. Sutton, presumably his wife, investigated the relationship between the diurnal pressure cycle and diurnal variations in air temperature (RSSA, 1910-1912, Vol. 2, pp. 341-356). His paper, "Do the mining operations affect the climate of Kimberley?" (SAPS, 1900, Vol. 11, pp. 7-17) may have been the first in South Africa on the subject of urban climatology. One of his favourite analytical tools was harmonic analysis, which he applied to most of his data, for example in a search for a relationship between soil temperatures (at Kimberley, Adelaide and Cordoba) and sunspot numbers for the period 1900-1918 (RSSA, 1922, Vol. 10, pp. 57-59). Four of his papers (RSSA, 1919-1921) dealt with "A possible lunar influence upon the velocity of the wind at Kimberley". Several papers in different journals dealt with the factors that determine the rate of evaporation from a water surface (1904, 1907, 1910, 1919, 1924). His observations of sunshine at Kimberley were published in the Meteorological Magazine (1897) and the Meteorologische Zeitschrift (1902). His work attracted attention internationally and in 1908 the University of Cambridge recognised his contributions by awarding him the degree Doctor of Science (ScD).
In addition to meteorology Sutton was involved in various other types of scientific work. After a mud rush caused the death of several mine workers in the Kimberley mine in 1894 he was asked to check whether this and other mud rushes were associated with prior heavy rains. This proved not to be the case, but he did find that each mud rush was associated with a fall in barometric pressure (SAPS, 1897, Vol. 9, pp. 54-66). Around that time he started daily observations of rock temperatures in the mine, at depths of about 300 m and 360 m, with a view to investigating possible long-term changes (Sutton, 1896). His results were later reported in "Earth temperatures at Kimberley" (SAPS, 1909, Vol. 18, pp. 421-435). He described an earthquake shock observed at Kimberley in Nature (1903), and drew attention to the possible role of atmospheric pressure changes in causing several shocks experienced at Kimberley (RSSA, 1913, Vol. 3, pp. 195-197). Other studies dealt with diurnal variations of the horizontal at Kimberley (RSSA, 1908-1910, Vol. 1, pp. 303-310 and 1912, Vol. 2, pp. 73-77) and the propagation of heat in water (RSSA, 1924, Vol. 11, pp. 85-91).
Several of his papers dealt with the mineralogy of diamonds, including, "The relationship between diamonds and garnets" (Nature, 1905/6), "Kimberley diamonds, especially cleavage diamonds" (RSSA, 1918), "Overgrowths on diamond" (RSSA, 1921), and "Inclusions in diamond from South Africa" (RSSA, 1921). His studies on this subject culminated in a monograph, Diamond, a descriptive treatise (London, 1928, 118p).
Sutton was elected a Fellow of the Royal Meteorological Society about 1903 and later became an honorary member. He joined the South African Philosophical Society in 1897 and in 1908, when this society became the Royal Society of South Africa, was elected a Fellow of the latter. He was a foundation member of the South African Association for the Advancement of Science (1902), represented Kimberley on its council for 1903/4, and in 1906 served as president of Section A (which included meteorology). He retired on pension in 1929.