The Bureau of Meteorology is now part of an international group sharing weather information with an impact on national security.

The alliance includes Australia, Canada, New Zealand, the United Kingdom and the United States.

In its latest annual report, BOM director Andrew Johnson says its relationship with Defence has deepened at all levels.

"The bureau is now supporting strategic decision-makers in key national security departments via a quarterly global seasonal outlook which identifies the potential impacts of adverse weather and climate on food security, refugee migration or conflict events," Dr Johnson said.

"This information supports decision-makers to take appropriate interventions or be cued to national security concerns much earlier."

The annual report highlights last year was the warmest and driest on record since consistent records began in 1910.

A summary of key weather events through the year is a stark reminder of the extreme bushfires, flooding, tropical cyclones, hail and dust storms Australians have endured.

Between July and December, more than five million hectares burned across Australia, with at least 18 lives lost and more than 1600 homes destroyed.

Most of the country experienced extreme heatwaves towards the end of December, resulting in increased ambulance call outs.

December 18 was the hottest day on record on average across the nation.

The annual report also notes a severe hailstorm that hit Canberra in January, and severe thunderstorms in Melbourne, resulted in more than $500 million of insurance claims.

Australian Associated Press