At the Hong Kong Observatory Headquarters, temperature readings are available since 1885, except for a break during the World War II from 1940 to 1946. Analysis of the annual mean temperature data showed that there was an average rise of 0.12°C per decade from 1885 to 2011. The rate of increase in average temperature became faster in the latter half of the 20th century. In post-war years from 1947 to 2011, the average rise amounted to 0.15°C per decade, accelerating to 0.23°C per decade during 1982-2011.