A South Australian policeman offers a drink of water to a koala at the side of the road
A South Australian policeman offers a drink of water to a koala at the side of the road in Adelaide January 16, 2014. Reuters

The month of May has set a new heat wave record in Sydney as beaching weather gets warmer throughout the month. According to reports, authorities have kept outdoor pools open longer than the usual operating hours to accommodate the swimmers.

Along with most of south eastern Australia, Sydney is in the middle of an autumn heat wave with a maximum daily temperature of five degrees or more. Weatherzone senior meteorologist Ben Domensino said last week was the warmest for the autumn season. Most of the region will also experience more or less the same temperatures five degrees higher than the average.

Last May 16, Adelaide's temperature of 27.4 degrees was the hottest recorded late into the autumn season while Hobart had 23.9 degrees on May 15. Bureau of Meteorology senior climatologist Blair Trewin said both Adelaide and Hobart had the warmest temperature ever recorded since more than a century ago.

Mr Trewin said it has been "significantly warmer" than the average temperature throughout the country. He added that Queensland and the Western Australian coast have only a "few cool pockets."

The Bureau of Meteorology previously declared 2013 the hottest year on record with average temperatures at 1.20 degrees Celsius higher than the long term average of 21.8C. In the bureau's Annual Climate Statement, average temperatures in 2013 broke the previous record in 2005 by 0.17C. The report revealed that all states and territories in Australia have above average temperatures on record in 2013. Northern Territory, South Australia and Western Australia were breaking records in terms of annual average temperature.

The hottest day for Australia was recorded on January 7, 2013. In the same month, Australia recorded its hottest week and hottest month since records began in 1910.

Australia's weather bureau has issued an alert for a significant El Niño event in July. Climate researchers have been seeing the start of what is described as the "most powerful El Niño" event since 1997 and 1998. An El Niño is a phenomenon in the atmosphere and Pacific Ocean. Extreme weather events in Australia like droughts and bushfires are caused by changes in temperature in the Indian Ocean. The weather bureau continues to monitor the changes in weather.