He meticulously collected vast amounts of meteorological data for years, and is considered as a pioneer in the collection of tropical meteorological data, to an extent unrivalled elsewhere until the 1820s. He had begun collecting detailed meteorological data as soon as he set foot in India, at Madras, and is known to have taken measurements three times a day, using Ramsden barometers and Nairne thermometers, made by then reputed scientific instrument makers, Jesse Ramsden and Edward Nairne. He trained under John Hope, who was the curator of the Edinburgh botanical garden as well an experimental physiologist. Roxburgh's interest in systematic meteorology may have stemmed from the influence of John Hope as well as his experiences at the Royal Society of Arts which, in the early 1770s, was greatly influenced by the climatic theories of Stephen Hales and Duhamel du Monceau. Such detailed measurements over many years led him to form an opinion on widespread famine and climate change in the empire.