The Welsh Government is looking to cut the summer school holiday in Wales and add another week to the autumn half term.
The proposals, which if given backing, will come into effect from September 2025, have been met with anger by a union representing headteachers in Wales.
Under the new proposal, a week would be taken from the start of the summer break and added to the October break, so that staff and learners get more time to rest during the long autumn term.
Teachers and pupils will still get 13 weeks of break, the Welsh Government says, but schools would get a two-week break in October 2025 and a five-week summer break in 2026.
The plans are being brought forward by the Labour Welsh Government as part of the Co-Operation Agreement with Plaid Cymru.
Reacting to the announcement of a formal consultation, which will open on Tuesday, 21 November, Laura Doel, National Secretary of NAHT Cymru, said: “We are bewildered as to why this consultation is taking place.
"No evidence has yet been presented that changing the school year would have any educational benefit for learners.
"And the previous consultation on this subject showed there was no real appetite for change, from parents, educators, businesses or the general public. So why is this continuing to be pushed as a priority right now?
“NAHT Cymru firmly believes that the basis of any reform should ensure the best provision and outcomes for learners.
"In fact, the little evidence available on school holidays shows that countries with much longer summer breaks than Wales have higher levels of attainment and suffer no significant loss of learning.
“With so much going on in schools right now, with a new curriculum, ALN reform, and severe recruitment and retention and funding crises, this just isn’t a priority for schools.
"Welsh Government would be better served in focusing on providing support to teachers and learners, and helping schools deliver current reforms, before embarking on any further changes to education.
“When school staff are being made redundant to balance the books, when schools should be prioritising delivering quality education to learners, and when we are deeply concerned about the recruitment and retention crisis, this should not be a priority for government.
“Additionally, we are concerned to see the inclusion of an implementation date in this consultation – it seems to beg the question whether this is a true consultation, or has the government made up its mind already?”
More changes in future
The consultation will also explore additional changes that could be taken forward in the future, but not from 2025.
These changes include the option of moving a second week from the summer break and adding it to the Whitsun break.
The Welsh Government says this would help make terms similar lengths and make the summer term more consistent, making it easier for pupils to learn and teachers to plan.
In this case, GCSE and A Level results days could happen in the same week.
The Welsh Government adds: "The proposal would also make the spring term more even and easier to plan for.
"The two-week break in the spring always coincides with Easter, which moves around.
"Keeping the spring break at a constant midpoint and separating it from Easter would make the term more consistent.
"Easter Monday and Good Friday public holidays would still apply, teaching time for these days would be made up elsewhere in the year."
Jeremy Miles, the Minister for Education and Welsh language said: “The long summer break can be a real strain.
"Families struggle to find childcare over the six weeks, and others struggle with the additional costs long summers bring. We also know our most disadvantaged learners suffer the most ‘learning loss’ from a long summer.
“There are plenty of examples of local authorities across the UK changing their school calendar to suit local needs.
“We want to make sure education works best for pupils, teachers, and families. We’re looking for people’s views on these changes and what it would mean for them.”
Designated Member Sian Gwenllian for Plaid Cymru added: "The current school calendar was designed a long time ago, under very different circumstances and we are suggesting changes that could work better for everyone, but most importantly for pupils of all ages.
“Many children and young people, especially those with additional learning needs and those from lower income families find the break very long, impacting negatively on their wellbeing and education.
"These proposals address that while still allowing the same amount of holidays throughout the year including a substantial summer holiday whilst also providing a longer break during the Autumn half term."