Schools feel pressured to provide a "sanctuary" for pupils living in poverty, as children often turn up for lessons without coats, hats and scarves, teachers have told Tes.
Teachers have reported feeling "helpless" as many of their pupils don't have the necessary clothing to keep them warm during the winter.
Shuaib Khan, a supply teacher who has worked in Peterborough and south Lincolnshire, said the number of children without winter coats has risen since he qualified as a sociology and humanities teacher four years ago.
And on one occasion, a teaching assistant organised a staff "whip-round" to buy coats for pupils.
"I remember once having a student arrive in soaked uniform as it had been raining and he didn’t have a coat," Mr Khan said.
"Clearly he had walked to school in ridiculously cold weather. Upon arrival, he went straight to the school canteen and got his free breakfast. Then sat by the radiator until lessons started. In class he was shivering and looked cold.
Disadvantaged pupils without coats
"A lot of the heat was generated by people in the classroom. But I remember students asking if they could stay at break or lunch just to stay warm. It was shocking as having a coat or heating is so taken for granted."
Mr Khan also recalled a teaching assistant using a hairdryer to help pupils dry their clothes after a rainy morning.
"This teaching assistant would even hand out hand warmers and use old lost and found gloves and scarves for free raffle prizes," he said.
Mr Khan added: "Seeing students cold and visibly malnourished, you just know as a teacher that they cannot work to their maximum potential. It’s sad because schools are trying so hard to make themselves a sanctuary for students.
"I definitely have seen fewer students with coats in my three or four years as a teacher. This could be down to the insanely overpriced nature of school uniforms.
"Some families need to decide on buying their child a good quality coat or making sure they have the correct uniform and/or stationery. This should never be a choice for any parent."
Michael Nott, an assistant headteacher at a Birmingham secondary, also said pupils turned up to lessons without winter coats.
"From my experience of working in schools in disadvantaged communities, coats are always an issue, with a lot of students not wearing them," he said.
"It’s very, very rare that they will wear scarves, gloves, etc. There is also the issue of students not wearing winter coats and instead coming into school in jackets and hoodies that are really not suitable for the winter conditions."
Kristina Murphy, who runs a free swap shop where pupils across the West Midlands can access warm clothing, told Tes she got referrals from schools as well as parents.
"We get referrals from teachers sometimes, although it’s more likely to be the pastoral team that contact us," she said.
An Essex primary teacher, who was kept anonymous for safeguarding reasons, told Essex Live: "They will come in school uniform and that is it. We can't say a lot to them, except, 'You should be wearing a coat to school now.'
"There's nothing really we can do except we can give them a spare jumper from lost property. It's sad and it's not right. Especially at the moment when you think of how cold it is. It's more kids than you think. I would say it's a third of the class. They come in and say they are cold or ask if they can stay inside."
Another primary teacher told the website: "You just feel sorry for them, really. You think they are coming into school without basic things that every child should have.
"I feel quite helpless. We do not have spare coats at school. We could provide them, obviously. If there was a coat in lost property, we can try and suggest that but sometimes they can be quite embarrassed by that."