A high-pressure system originating from the Pilbara region is set to bring extreme heat, thunderstorms, and fire danger to Sydney on Wednesday, following record-breaking temperatures in inland NSW towns like Tibooburra and Cobar.

Forecasts indicate that Sydney's temperature will peak between 2pm and 3pm, potentially reaching 39 degrees Celsius, which could mark the hottest October day on record for the city.

Yesterday, inland NSW locations surpassed previous October heat records, with Tibooburra hitting 42.8 degrees and Cobar reaching 42.4 degrees.

Currently, the temperature in Sydney is 19.7 degrees Celsius, with expectations of rising by about 20 degrees throughout the day.

This intense heatwave is linked to a rare 'sudden stratospheric warming' event over Antarctica, which has contributed to the temperature spike and historically increases bushfire risks and dryness in Australia.

The ongoing extreme weather is driven by climate change, which is causing heatwaves to last longer and occur more frequently, with a recent climate risk assessment warning of a significant rise in heat-related fatalities in Sydney if global temperatures increase by 3 degrees.

The Bureau of Meteorology has issued warnings and is actively monitoring the situation as Sydney prepares for its hottest October day, emphasizing the importance of public safety.