John E. Davies entered the army at the age of 17 and served in Mauritius for some time before being posted to the Cape of Good Hope. During the Eighth Frontier War (1851-1853) he saw active service at Fort Beaufort, for which he was awarded a medal. After leaving the army he was in business for some years in Grahamstown and Port Alfred, before being appointed superintendent of Albany Hospital, Grahamstown, in 1874. He held this post until his death in 1891, following an operation for an abscess. He was remembered as a good administrator, a kind person and family man, and was a lay preacher in the Wesleyan Church for 30 years.
In 1878 Davies began regular meteorological observations for the Meteorological Commission of the Cape of Good Hope, providing the first such data from Grahamstown. A summary of his results was published annually in the Commission's Reports. He continued his observations until his death, a period of almost 14 years.