Six children died and three were injured when a freak wind gust lifted the castle and several inflatable balls into the air during end-of-year celebrations on December 16, 2021.
The commemoration will be held not far from the school at Devonport's Market Square on December 15, Premier Jeremy Rockliff announced on Tuesday.
"As we approach the first anniversary of the devastating tragedy ... we continue to keep the children, their families and their loved ones in our hearts and minds," he said.
"Families, friends and the community are invited to attend the ceremony to formally remember and honour the lives of the six children lost that day."
Mr Rockliff said the ceremony was being held after consultation with families and the community and would be an opportunity for people to leave flowers and messages of support.
Some $1.4 million was raised for the families of victims Zane Mellor, Peter Dodt, Jalailah Janyne-Marie Jones, Addison Stewart, Jye Sheehan and Chace Harrison.
An inquest into their deaths, which may formally begin next year, is expected to hear from weather experts and eye-witnesses.
An administrative inquest hearing was told the wind gust was like a powerful and concentrated "mini tornado" and the castle and inflatable Zorb balls were lifted to a "great height".
The court was told there were 39 students on the oval at the time and grade five and six children were taking part in activities during a 55-minute window.
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