Narooma is a small town on the coast of New South Wales, Australia about 300km south of Sydney. This note presents a plot of the annual rainfalls recorded at Narooma over the past 106 years (1910-2015).
Official records of rainfall in Narooma exist from 1 January 1910 when observations commenced at the Narooma Pilot Station. This is the same location where Narooma rainfalls are still recorded manually each day by volunteers from Marine Rescue NSW (formerly the Royal Volunteer Coastal Patrol).
Unfortunately the Narooma records are incomplete or missing for 22 of those years (1919-1925, 1961-1962 and 1980-1992), but estimates of the rainfall at Narooma could be made for those periods from observations at Narooma Bowling Club (1km away) or Bodalla (15km away). The Bodalla data were adjusted for the 1919-1925 and 1961-1962 periods, while the Narooma Bowling Club data were used for the 1980-1992 period. The rainfalls estimated from Bodalla and the Narooma Bowling Club were based on simple correlations of monthly rainfalls for overlapping records at these stations and at Narooma.
The plot of the composite (ie recorded + estimated) annual rainfalls at Narooma from 1910 to 2015 shows that the rainfall has varied cyclically but consistently over the past century without any long-term trends. The average annual rainfall was 928 mm, but this has varied between 406 mm (in 1982) to 1774 mm (in 1934).
The graph shows the cyclic nature of annual rainfall at Narooma (as occurs elsewhere) with drought periods occurring every 10-15 years (with a few exceptions such as in the 1930s and the 1990s).
The monthly rainfall data used, all raw, for this analysis (except for the Narooma Bowling Club) were downloaded from the Australian Bureau of Meteorology website: http://www.bom.gov.au/climate/data/index.shtml