If you thought Sydney had been warm over the past year or so, you'd be right.

Last year was the city's equal warmest for overnight temperatures and its second-warmest for means and maximums in 156 years of record keeping at Observatory Hill.

Another hot year for Sydney. Photo: Simone De Peak

For some temperature measures, such as for NSW heat, the previous record had been set only a year earlier.

Advertisement

Agata Imielska, senior climatologist at the Bureau of Meteorology in Sydney, said it was "quite surprising" to see last year eclipse 2013 given the bar had been set so high.

"We just didn't have the cool periods," Ms Imielska said. "There was a real persistence in the warmth."

All of NSW was very much above average or highest on record for temperatures in 2014. Photo: BoM

Sydney's mercury climbed past 25 degrees for a record 140 days in 2014, beating the previous high of 134 in 2001, and well in excess of the long-run average of 88 such days. Just 54 nights dropped below 10 degrees, the third fewest on record, with 88 days again the number for a typical year.

2014 was also Sydney's driest year since 2005, with the 893.8mm of rain, about a quarter less than average despite a flurry of thunderstorms and including the city's longest recorded stretch of seven days last month.

Rainfall was mixed over the state in 2014. Photo: BoM

Nationally, mean temperatures in 2014 came in 0.91 degrees above the 1961-1990 average, behind only 2013 and 2005, the bureau said in its annual report. Rainfall was slightly above average, with the north unusually wet and the south largely drier than normal.

Globally, 2014 was the hottest year on record, the Japan Meteorological Agency declared this week. Land and sea-surface temperatures were 0.27 degrees above the 1981-2010 average, easily eclipsing the previous highs set in 1998, 2010 and 2013.

"Global warming is contributing to these heat records, and it's very unlikely that we would have seen the proliferation or the frequency of these heat records around the world without the influence of global warming," Karl Braganza, head of climate monitoring at the bureau, said.

Nationally, relatively warm days outnumbered cold ones by 3:1 in 2014. Photo: BoM

"The climate system we live in ... that's all about 1 degree warmer than it used to be," Dr Braganza said.

Warm and dry

For NSW, 2014 was the hottest on record for mean temperatures and the equal warmest for maximums. Among the other states, only the Northern Territory failed to notch a year among the four warmest on record.

As is usual, rainfall varied across the state, with totals about 16 per cent below average. North-eastern NSW was much drier than normal, and state-wide spring totals were the 11th lowest on record, the bureau said.

For the second year running, rainfall in the key Murray-Darling Basin region fell short, dropping 15 per cent below average, sending storage levels lower. In 2013, rainfall in the region was 24 per cent below par.

Only one month in the past two years – February 2014 – was cooler than the national 1961-1990 average used as a gauge. For Sydney, the last month of below-average mean temperatures was December 2011 – 36 months ago.

Nationally, warmer-than-average days exceeded anomalously cold days by three to one in 2014.

Aside from the background warming caused by climate change, Australia's unusual warmth has been influenced by the near-El Nino conditions in the Pacific. During El Nino years, the western Pacific tends to be hotter and drier than usual, while nations on the ocean's eastern fringe are relatively cool and wet.

"If we maintain the current conditions in the Pacific, then it's likely we'll see the warmer-than-average conditions persist into 2015," Dr Braganza said.