John Matthew Fairweather was born in London, England on 15 February 1882 and was articled to Robert Scott in Arbroath, Scotland. He moved to Ireland in 1902 and worked as an assistant to Anthony Scott & Sons in Dublin. In c.1907 he formed a partnership, Fairweather & Robertson, with (?) Robertson in Dublin. They submitted an entry for a competition to design buildings for the Scottish National Exhibition held in Edinburgh in 1908. Their designs are illustrated in British Competitions in Architecture vol. 2, no. 14, December 1907 (pp. 67-69). The partnership may have been formed specifically to enter the competition and, as they weren't successful, have been dissolved after this.
In 1910 Fairweather was appointed Assistant Architect at the Architect's Department of the Board of Works. He worked in Mallow, Co. Cork and in Cork City until 1915 when he transferred to Dublin. In 1923 he was made Assistant Principal Architect and in 1939 Principal Architect at the Board of Works.
Fairweather was elected a member of the Royal Institute of the Architects of Ireland (RIAI) in 1920 and a Fellow of the RIAI in 1940. He was Vice-President of the RIAI in 1946 and 1949, and President of the RIAI in 1950 and 1951. He was also elected a member of the Architectural Association of Ireland (AIA) in 1919. He died in Dublin on 19 January 1962
For a list of principal work by Fairweather see Dictionary Irish Architects 1720-1940 [link below]