It was almost 40 degrees outside the City of Greater Bendigo Brass Band's rooms during this week's practice, and arguably about the same temperature inside.

But band members and singers from the Bendigo Youth Choir were undeterred, playing songs about reindeer and decking the halls.

The Rotary Club of Bendigo Carols by Candlelight will be the band's third Christmas performance this year.

"That's a quiet year for us," musical director Cally Bartlett said.

Devoting the last Sunday before Christmas to playing the carols has been an annual tradition for many of the band's members. Some have been involved for almost a decade.

The band plays a set on its own, plus accompanying the community carols.

"Musically, everyone has to be quite on the ball," Mrs Bartlett said.

"There is a lot of flexibility that has to happen on the night."

All of the people involved in the carols are volunteers.

"It's all done because they want to do something for Christmas for Bendigo," Valerie Broad, one of the event's long-serving volunteers, said.

"I think that's pretty special."

The carols as we know them today have been a part of Bendigo for 49 years.

Mrs Broad has been involved, in one way or another, since they started.

"It's a very, very essential part of Bendigo," she said.

"Give us a good night and we can attract 7000 people to that park.

"It is a wonderful introduction to Christmas."

Fellow long-serving volunteers said Mrs Broad's musical knowledge and contacts had been essential to the event's success.

The Bendigo Youth Choir, which she founded, has been part of the event for most of its history.

"It has always been a great asset," Bendigo man Jim Mahoney said.

He was part of the committee that established the carols, 49 years ago. Mr Mahoney was formerly a carols committee chair and deputy chair.

The 84-year-old is believed to be the only member of that committee still involved in the initiative.

"I've never been to any other carols at all," Mr Mahoney said.

He said the committee was established to look at new projects involving the Rotary club.

"There was no major event [at Christmas] like we have now," he said.

Others had tried to establish Carols by Candlelight in Bendigo, but Mr Mahoney said it "hadn't stayed".

"We had more people to run it," he said.

He likened the first year the club staged the event to a trial - something they, too, weren't sure would stick.

"We were delighted at the response," Mr Mahoney said.

"We had a good night - the weather was fine."

He said Rosalind Park had always been the favourite among the Bendigo people as a carols venue.

Staging the event there hasn't been without its challenges. Mr Mahoney said there were several years when the carols had been rained out.

"Several years ago we went to the town hall, but that was too small," he said.

There were some years when the weather meant the carols couldn't be staged at all.

Wet conditions almost meant the 2016 carols were washed out, but the weather held out in the end.

Mr Mahoney said there was a sound shell in Rosalind Park back when the carols started.

The staging process has since changed.

Volunteers start setting up about 6.30am on the Sunday.

The stage and the backdrops were among the biggest jobs, but volunteers also needed to wheel out all the rubbish bins and set up the tables at each gateway.

Entry to the carols was free, but Rotary volunteers appreciated gold coin donations for a set cause. This year, Rotary Club of Bendigo president Dr Michael Pearson said funds raised would support Bendigo Community Health Services.

The club is expecting about 5000 - 7000 people to attend the event.

Dr Pearson said pretty much every member of the club was involved in the carols.

Numbers would be boosted by volunteers from Bendigo Bank, one of the event's sponsors, this year.

There were barricades, generators and mobile toilets to get in place.

A marquee was usually erected for entertainers to use and there was some seating to set up.

Sound checks needed to be conducted once the set up was complete. Then, there was staging the carols themselves.

Everything that had been set up needed to be packed down again at the end of the evening.

Volunteers usually finished before midnight.

Shortly after one year's carols finished, planning for the next began, with permits and permissions to be arranged and candles and programs to be obtained.

"We all have our set jobs," Mr Mahoney said.

Organising the equipment used to be his job. Some health challenges meant he had pulled back on his commitments this year, aiming instead to make a brief appearance at the carols.

"It's a magical night," Mr Mahoney said.

"It's a very happy night."

Even after all the years of being involved in staging the carols, he would look out on the night and see people of all ages enjoying the festivities.

"The kids really love it. It's great to see," Mr Mahoney said.

The Rotary Club of Bendigo Carols by Candlelight starts from 6pm on Sunday at Rosalind Park.

Pre-event entertainment runs until 8pm, when the event is officially opened by Bendigo mayor Margaret O'Rourke and the club's president.

The children's section of the program runs from 8pm - 8.30pm, followed by the main program from 8.30pm - 9.30pm.

Santa arrives at 9.30pm.

Attendees are advised to bring their own chairs and blankets.

The temperature in Bendigo on Sunday is predicted to reach a top of 29 degrees, with southerly 15 - 20km/h winds in the evening. There is no predicted rainfall.

Bendigo's Christmas forecast is a mostly sunny day with a maximum temperature of 36 degrees. Light winds becoming southerly 20 - 25km/h are expected, but no rain.

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