The Canberra Aqua Park opened on Saturday for the summer season.

Kids and adults alike enjoyed the tunnels, bridges, slides and swings on the obstacle course located at Black Mountain Peninsula.

Canberra Aqua Park operations manager David Watts said there were many bookings for the park over the weekend.

"Canberra has embraced it and we're getting good numbers," he said.

It is the second year the 1400-square-metre park has been erected, following a trial of the water park last summer. The trial was largely successful, although it was affected by the bushfire smoke haze and freak hailstorm.

This year the park has had to reduce the number of customers allowed in at any one time, due to the COVID-19 pandemic. Bookings are in one-hour sessions.

Weather for the opening weekend of the park was varied. It was mostly fine on Saturday morning and early afternoon but a thunderstorm hit the capital in the late afternoon.

It was mostly sunny on Sunday but it was windy. It reached a top of 27 degrees.

"We've had a bit of a mixed bag, there was a thunderstorm on Saturday afternoon but it was a good day. We had plenty of customers come through and the conditions in the main were very good," Mr Watts said.

"[Sunday was] a beautiful day by the lake, it was a bit windy but very safe."

It came as many parts of NSW experienced a heatwave over the weekend. Parts of Sydney recorded temperatures of more than 40 degrees on both Saturday and Sunday.

As well, much of northeast NSW broke the 40-degree barrier.

A total fire ban was issued for most of eastern and northeastern NSW on Sunday.

But Bureau of Meteorology meteorologist Helen Kirkup said the ACT had escaped the heatwave.

"It isn't heating up as quite a lot of other places," she said.

Canberra was forecast to reach up to 35 degrees on Sunday at one stage but a cool change for a gusty southerly hit the nation's capital earlier than expected. As well, Dr Kirkup said cloud cover had kept the temperature down.

IN OTHER NEWS:

Canberra recorded wind gusts of more than 50km/h on Sunday.

There was a severe weather warning for damaging winds in areas surrounding the ACT on Sunday.

Dr Kirkup said Braidwood had wind gusts of more than 90km/h and Nerriga had a wind gust of 109km/h.

While the nation's capital avoided the weekend heatwave it is forecast to reach 35 degrees on Tuesday, the first day of summer.

A top of 26 degrees is forecast for Monday, it is expected to be partly cloudy with wind gusts of up to 20km/h.