Children have been told to wear coats and scarves in lessons after teachers opened classroom windows to counter coronavirus.
Lytchett Minster School in Upton, near Poole, Dorset, said classroom doors will also be left open to improve ventilation.
It comes as the Met Office issued snow and ice warnings for much of the UK over the next two days, with sub-zero temperatures expected.
The 1,400 11 to 18-year-old pupils at Lytchett Minster School also now have to wear face masks in the classroom, corridors and communal areas.
According to The Sun, headteacher Andrew Mead said: “They will be wearing face coverings in classrooms, corridors and other communal areas.
“Classrooms will be well ventilated with doors and windows kept open as much as possible.
“In view of this, we are allowing students to wear coats and scarves in lessons."
Mr Mead said that wearing face masks for ‘five hours a day’ may be uncomfortable, but it was a ‘price worth paying’ to keep schools open.
He added that pupils would have to take a lateral flow test on their first day back – and should continue taking tests at home.
It comes after the Government ordered secondary school pupils to wear masks in school upon their return from the Christmas break.
Ministers hope the masks will help stop the spread of the virus and limit the Omicron variant causing staff absences that disrupt education.
Education Secretary Nadhim Zahawi said face coverings would be required until January 26.
Mr Zahawi said: "The painful lesson we learnt was when children weren't in school, the impact on their mental health and, of course their education, was quite substantial.
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"Which is why I'm so determined, as is the prime minister, to make sure education remains open and children are in the best place when they're in the classroom, with their friends, learning in front of a teacher."
In England, new rules were reintroduced in December to try and slow the spread of the virus in the lead-up to Christmas. Plan B restrictions mean that face coverings are required in most indoor public spaces and on public transport.
The new rules involving masks in secondary schools are in addition to this.
A full list of the places where a mask is required can be viewed here .
