Issued 5^th January 2004

Another warm year, with a return to near normal rainfall totals

Australia experienced warmer than normal conditions across much of the country in 2003. Preliminary data indicate that the all-Australian annual mean temperature for 2003 was 0.62°C above the 1961-90 average, making it Australia’s sixth warmest year on record since 1910. Australia’s annual mean maximum temperature was 0.65°C above normal (sixth highest), with the mean minimum temperature being 0.59°C above normal (fourth highest).

Australian mean temperatures are calculated from a network of about 100 high-quality, mostly rural observing stations throughout the country. The temperature records at these locations have been adjusted for artificial discontinuities caused by changes in instrumentation and location. Many of the sites are included in Australia's contribution to the Global Climate Observing System - a comprehensive network established to monitor long-term climate trends and variability.

The general rise in Australian temperatures during the second half of the 20th century is in line with global warming trends indicated by independent records from surface observation networks (land and ocean), weather balloons, satellites and glaciers. According to a preliminary estimate released by the World Meteorological Organization (WMO) on 16 December 2003, the global mean temperature for 2003 was the third warmest on record (since 1861). In 2001 the Intergovernmental Panel on Climate Change (IPCC) concluded that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”.

Australian rainfall for 2003 was largely influenced by the breakdown of El Niño conditions in the equatorial Pacific Ocean early in the year. Preliminary data indicate that the average rainfall throughout Australia for 2003 was 476mm, very close to the long-term average of 472mm. However, recovery from the rainfall deficiencies that accumulated during the severe 2002/03 El Niño-related drought was slow and patchy, with some parts of eastern Australia yet to see a full recovery. Australia’s area-averaged rainfall is calculated from a network of around 5000 rainfall stations, most of which are staffed by volunteer observers.

Temperature observations averaged over each State reveal that Queensland had the highest temperature anomalies with a mean maximum temperature anomaly of +0.91°C and a mean minimum temperature anomaly of +0.99°C. These anomalies were reflected in shifts in the numbers of hot days and cold nights reported. State rainfall totals for 2003 remained below normal in Queensland, New South Wales and Victoria, although these were all significantly above the totals for 2002.