Weather bureau forecasts a hot weekend in Queanbeyan

The heat arrives just as tens of thousands of rev heads pour into Canberra and the region for the annual Summernats car festival.

Festival organisers said they were prepared with water and sunscreen to hand out to patrons, and have warned everyone to take it easy in the heat.

ACT Rural Fire & Rescue has also updated its fire danger forecast rating for the weekend to very high.

The heat arrives on Saturday with forecasters expecting a top of 36 degrees during the day.

The hot day is also likely to turn into a warm night.

Bureau of Meteorology forecaster Steven Stefanac said the bureau expected a minimum of 21 over Saturday night, so "quite balmy for Canberra".

Sunday heats up to an expected 37 or 38 degrees around the region with a shower or two also expected.

Summernats co-owner Andy Lopez warned patrons about the hot weather.

"Our advice, take it easy, drink water, moderate alcohol consumption. We do have free water around the site available to patrons," Mr Lopez said.

He said there would be crews to offer water and sunscreen to those who may be queuing for tickets.

Festival staff would also be working hard to get people through the gates quickly, he said.

"We have fantastic first aid and medical should anyone get affected by the heat. Our RSA policies for service of alcohol are second to none.

"It is going to be hot, we encourage people to take it easy, take care of yourselves, take care of your mates and if you need it, we will be here to take care you of as well."

Bureau forecaster Mr Stefanac said the heat was caused by a high pressure system over the Tasman Sea drawing hot air from northern Australia.

The air was drawing southwards across south eastern Australia and affecting Queanbeyan, the forecaster said.

Moving across to the coast, Mr Stefanac said the prediction for Batemans Bay was for cooler temperatures.

Saturday has a top of 32 degrees and mostly sunny.

Sunday was expected to be partly cloudy and reach a top of 33.

"On Sunday a change comes pretty early in the day, and it doesn't have a chance to reach the hotter temperatures," Mr Stefanac said.

The rest of the week in Queanbeyan looks warm with a few showers into Thursday.