For some, it's time to spread the picnic blanket on the grassy banks of the lake with many families reserving an early vantage point to view the evening's fireworks.

Parents looked nervously at the sky fearing a repeat of the hail storm that battered Canberra on Monday night with nearly 600 calls for help received by emergency services.

Space on the hill at Commonwealth Park was at a premium by 6pm with games of frisbee and cricket spreading to Gallipoli Reach, where a citizen ceremony was held a few hours earlier.

Others decided to spend the Australia Day in a more innovative fashion by building a 70-metre slide in Yarralumla's Stirling Park.

Ben Appleton, 29, spent his morning assembling the slide for those seeking some adventurous fun and relief from the humid conditions.

"This is our first year doing this and we get it out every Australia Day," he said. "We had close to 30 people using the slide in the afternoon with many getting involved after stumbling across it."

Mr Appleton said the slide was used by children and seniors alike with a 75-year-old woman making numerous runs.

"She had lost her son in Afghanistan and was feeling sad on Australia Day, so we were glad she got some joy out of it."

At the National Museum of Australia, families enjoyed talks, music and performances from Indigenous artists and elders.

"I think what the museum is doing here is really quite significant, especially today being Australia Day, by embracing the first peoples of our country," said Adrian Brown, a Ngunnawal Country Ranger in the ACT Parks and Conservation Service.

Westside Acton Park hosted the CBR Hottest 100 Beach Party, with a giant water slide, a sunset screening of Australian film The Castle and Triple J's Hottest 100 countdown.

Tessa Martin from Isaacs was impressed with the set up at the 18+ event, with blow-up pools, sports to play and bars.

"I hadn't been to this area yet, but it has been really fun," she said. "I think if more people know about it, it would be even more pumping."

Organiser Ashleigh Gleeson said she was relieved the weather held out for the first-time event, which attracted about 300 people.

Other celebrations around the city included a blow-up pool party at La De Da in Belconnen, a family day on the Canberra Southern Cross Yacht Club and a lakeside concert at the National Carillon.

The National Film and Sound Archives marked the occasion by screening some classic Australian films.