Schools closed as NSW swelters

Temperatures across the regions are expected to exceed 40 degrees Celsius in parts as the Rural Fire Service prepares for an increased bushfire risk.

The state's education department announced 20 public schools, largely across the Riverina, would be closed due to the heat.

Updated forecasts from the Bureau of Meteorology revealed hot weather across parts of the state, with Griffith expected to top 45 degrees and Wagga Wagga hitting a maximum temperature of 39 degrees.

Further north, Dubbo will hit 41 degrees Celsius.

The warning was issued for the Mid-North Coast, Tablelands, Snowy Mountains, metro Sydney, Hunter, Illawarra, Riverina, South West Slopes and both the lower and upper Western Districts.

Slightly cooler temperatures are expected in the capital city, with Sydney expecting a top of 30 degrees on December 8 before temperatures rise heading into the weekend.

Sydney will reach 39 degrees Celsius on Saturday, with similar weekend conditions expected in Bathurst, Tamworth and Wollongong.

Bureau of Meteorology community information officer Daniel Hayes said some parts of the state may experience the heat for a number of days to come.

"Southern and coastal areas can expect to see a cooler change on Sunday," he said.

"But with the heat trough lingering over the northern parts of the state we can expect hot temperatures in those areas right into most of next week."

Mr Hayes said said people needed to keep an eye on government websites, ensure they were staying hydrated and to check on their neighbours as the hot weather lingers.

"In general it comes down to staying hydrated, staying out of the sun if you can and avoiding the outdoors on the hottest part of the day," he said.

"Please be aware of the weather and keep an eye on vulnerable members of our community as well as animals."

Alerts from the NSW Rural Fire Service reminded residents stay up to date on any bushfires in their area, remain alert and review bushfire safety plans.

NSW public schools closed due to heat: