Experts warn of more intense downpours as mercury continues to climb

It has been a summer of record-breaking heat, and leading Sydney climate experts have warned of more intense weather events as the mercury continues to climb.

Data from the Centre of Excellence for Climate System Science predicts a two-degree rise in average global temperatures, meaning 10-30 percent more rain could be dumped on Sydney during extreme downpours.

"When that rainfall event does occur, it will be short and sharp and there will be lots of flash flooding," Sarah Perkin-Kirkpatrick from Climate Change UNSW told 9NEWS.

"We need to build better infrastructure to cope with these flooding events because we will certainly see more extreme rainfall regardless where you are."

While some parts of the continent will become wetter, others will experience increased drought.

Water parks spilled over today as Sydneysiders tried to cope with the extreme temperatures, with Penrith experiencing a top of 42C.

Meanwhile, Bathurst and Newcastle are expected to swelter through their hottest January night on record.

The NSW Rural Fire Service has declared a total fire ban for Sydney and surrounding areas from midnight tonight and all through tomorrow.

READ MORE: Total fire ban declared for Sydney and surrounding regions tomorrow