Parts of eastern and central Australia have just recorded their coolest summer in more than a decade, but La Niña's loosened grip meant rainfall was well below recent years.

The low temperatures were abnormal as climate change now ensures the vast majority of seasons are warmer than past years, even when the cooling influence of La Niña is present. 

Statistical highlights included Canberra's coolest summer nights in 38 years and Sydney's coolest in 23 years.

Rainfall was well above average across northern Australia and it was the wettest summer on record for small parts of the central Northern Territory, Kimberley and Cape York Peninsula.

Rain was variable but mostly below average in southern areas, including record dry conditions on the south-west tip of Western Australia and just 1.4 millimetres in Perth — only four per cent of its average.

Range of drivers behind cool summer

In many ways, the cool summer temperatures compared to recent years played out as expected due to the balancing of two climate drivers, the warming influence of climate change and the cooling of La Niña.

The wildcard this summer was a spell of unusually cold weather over south-east states in December, with temperatures as much 15 degrees Celsius below normal and five days of snow recorded in the alps.

Another factor was a pattern of persistent easterly winds across southern states, which during summer brings cooler and wetter weather to Sydney and Canberra, but warmer and drier weather to Perth.

The anomalous easterly winds deviation has been a feature of the weather across south-east Australia for more than a year, and was partly behind Sydney's wettest year on record in 2022.

Sydney

Sydney's summer was wet and relatively cool, although extremely high humidity caused January to feel warmer. 

The city recorded its coolest summer days in 11 years even though the average maximum of 26.4C was slightly above the long-term average of 25.7C.

Despite a spell of warm and humid nights during the second half of summer, minimums were the coldest in 23 years at 18.3C, a touch below the long-term average of 18.4C.

The Harbour City was drenched by several severe thunderstorms which lifted the rain total to 447mm, well above the average of 297mm but well below last summer's 655mm.

It was also Sydney's fourth consecutive summer that was wetter than normal. 

Melbourne

Melbourne enjoyed a relatively cool and dry summer, although passed the 40C mark for the first time in three years.

The city's traditional extreme day to day variability brought maximums ranging from 40.5C to 15.8C.

Its rain total of 86mm was the lowest in nine years and well below the average of 154mm.

Maximum's averaged 25C, slightly below the long-term average of 25.4C, but warmer than an unusually cold summer two years ago.

While days were cool, nights were on the warm side averaging 15.2C, more than a degree above the long-term average of 14.0C and the 27th consecutive summer with warmer than normal nights.

Brisbane

Brisbane's summer was dry and relatively cool.

Only 269mm fell in the city, well below the average of 446mm and the driest summer in four years. 

Despite the lack of rain maximum temperatures were close to normal, averaging 29.6C, a touch above the long-term average of 29.3C.

Nights were pleasantly cool compared to recent years averaging 20.4C, just below the long-term average of 20.5C and the lowest in 11 years.

This dragged the city's mean temperature, the average of all minimums and maximums, to also to the lowest level in 11 years.