Australians are more likely to die during unseasonably cold winters than hotter than average summers, QUT research has found.
Across the country severe winters that are colder and drier than normal are a far bigger risk to health than sweltering summers that are hotter than average.
QUT Associate Professor Adrian Barnett, a statistician with the Institute of Health and Biomedical Innovation and the lead researcher of the study, said death rates in Australian cities were up to 30 per cent higher in winter than summer.
The researchers analysed temperature, humidity and mortality data from 1988 to 2009 for Adelaide Brisbane, Melbourne, Perth and Sydney.
Professor Barnett said the finding that hotter or more humid summers had no effect on mortality was "surprising".
"We know that heatwaves kill people in the short-term, but our study did not find any link between hotter summers and higher deaths," he said.
"The increase in deaths during colder winter could be because Australians are well-prepared for whatever summer throws at them, but are less able to cope with cold weather. There isn't the same focus on preparing for cold weather as there is for hot weather, for example through public health campaigns or even wearing the right sort of clothes.
"The strongest increase in deaths during a colder winter was in Brisbane, the city with the warmest climate, with an extra 59 deaths a month on average for a one degree decrease in mean winter temperature."
"Brisbane has the mildest winter of the five cities but has the greatest vulnerability. We believe this is because most homes are designed to lose heat in summer, which also allows cold outdoor air to get inside during winter."
Professor Barnett said the findings of the study, published in the journal Environmental Research, could trigger more prevention programs to help reduce the future burden on the health system.
"Excess winter deaths have a significant impact on health systems across Australia," he said.
"There are extra demands on doctors, hospitals and emergency departments in winter months, especially for cardiovascular and respiratory diseases which are triggered by exposure to cold weather.
"Our findings show the winter increases in mortality are predictable so ramping up public health measures, such as influenza vaccinations and insulating homes, particularly for vulnerable groups, should be considered to try to reduce the impact of severe winters."
*Individual city data is available*