The earliest Easter since 1913 is playing havoc with school planning and teachers' personal lives.
Easter Sunday falls on March 23 this year. More than two-thirds of authorities will close schools over the public holiday and delay the two-week break until early April.
But many are still taking their main break from Good Friday onwards and will face a longer, potentially exhausting, summer term.
There are also concerns that a spring half-term of fewer than five weeks in some authorities will mean unruly pupils will barely settle back into work.
One languages teacher at a Hertfordshire secondary said: "The school will never get into a rhythm. You can write off the first week and the last week of term. We will get very little done.
"It's going to feel like we're cramming a lot of exam preparation into a very short space of time and I dread our 14-week summer term - the autumn term was 15 weeks and it almost killed me."
The uncoordinated breaks mean more teachers than ever will miss spending holidays with their children or partners at schools in neighbouring authorities.
James Looker, 29, a teacher at Forestdale Primary in Croydon, will not spend the holidays with his wife, Claire, as she works in an independent school and her holiday will start a fortnight before his.
"It's a shame, but I think taking the Easter weekend as a separate break is a good idea," he said.
This year's unusual calendar has already led to two spring half-term break dates.
One Home Counties secondary headteacher, who asked not to be named, said he would miss out on spending both half-term and Easter with his wife as she works at a school in another county.
Unsynchronized holidays also create difficulties for scheduling job adverts and interviews, as applicants are away at different times.
"The rhythm of the school needs to be carefully thought out," the head said. "The early Easter holiday will be disruptive to patterns of exam preparation."
Steve Sinnott, general secretary of the National Union of Teachers, said the confusion this year was "the worst situation" he had ever seen. He said both the early Easter and a lack of guidance for local authorities was responsible for the disruption.
News of the confusion comes as the Local Government Association announced that only two thirds of authorities had adopted its preferred "standard school year", made up of six more equal half-terms.
The association highlighted that nine million families with children at schools in different authorities could save pound;500 each in childcare if term dates were synchronized.
One teacher, however, summed up the potentially good side of an early Easter on the TES online staffroom: "This is a (rubbish) term and the faster we get it over with, the better."