Boys have protested their schools' "no shorts" policy by wearing dresses to classes during the heatwave.
Several schools, including Ysgol Bro Dinefwr in Llandeilo, Carmarthenshire, doubled down on their rule despite the scorching 30C temperatures the UK has experienced this week - conditions hotter than Benidorm.
The secondary school, which caters for more than 1,100 pupils, insists black trousers are always appropriate.
So Oscar Ralph, 13, went to lessons in his eight-year-old sister's skirt - and says no one minded. His family even supported Oscar's stance, Wales Online reports.
"We have asked if we can wear shorts and it's their decision that we can't. So I borrowed my sister's skirt," Oscar said today.
"There was a bit of fun and jokes about it, but nothing nasty. The teachers said nothing. It was a lot easier to work not being distracted and so hot. In trousers, I was constantly sweating."
Oscar's parents, Hannah and Andrew, admitted they were “a bit apprehensive” when their son told them what he was wearing to school.
After talking to him, they supported his decision, saying the teenager loved school and didn’t want to cause any trouble, but was too hot in trousers.
“We were not sure if he would get in trouble or made fun of,” said Hannah.
"Shorts are not allowed, but skirts are part of the uniform, so they can't stop him."
Oscar borrowed his sister’s grey primary school uniform skirt, which was the right colour, but it had to be fastened with a safety pin. He wore it with his usual school shoes, shirt and tie.
“I know parents have asked about wearing shorts and have been told no. It’s been too hot for trousers, especially black ones," said Hannah.
“He looks a bit like a Celt in a shirt, tie and skirt. He walked the 1.6 miles to school on his own as usual, dressed in a skirt, it’s very brave. His friends know about it. They weren’t keen to do it too, but I hope he’s started a trend.
“I can’t think of a rational reason why boys are not allowed to wear shorts when girls are allowed to wear skirts. It doesn't seem logical. It’s a lovely school and he loves it there. It’s a very nice school and proof of that is that he’s not been reprimanded for wearing a skirt."
Oscar’s dad, Andrew, said he was proud of his son for taking a stand. He admitted he doubted he would have done the same as a teenager.
The 38-year-old man, who works in finance, said: "He has got some bottle. I don’t think I could have done this at his age. I am really proud of him. It’s crazy not allowing them to wear shorts to school in this weather."
And boys at Ysgol Maes y Gwendraeth, in Llanelli, also in Carmarthenshire, went in wearing skirts too. Levi Smith, 15, said it was too hot to concentrate wearing trousers and he was sitting important year 10 GCSE exams.
Levi said: "It was frustrating because I could not concentrate it was so hot. I had exams today, yesterday and more tomorrow.
"Six of us went in in skirts we borrowed from friends. The school didn't say anything. We all just carried on as normal. It felt much nicer and more comfortable in the heat wearing a skirt. No one made fun of us.
"I had a Welsh exam today and it was fine. We are not allowed to wear shorts but they can't stop us wearing uniform skirts."
Levi's mum said parents had asked the school if their sons could wear shorts but had been told no. She said they risked detention and being sent home if they didn't comply and she would rather Levi wore a skirt than missed school or couldn't concentrate sitting his exams.
Levi's pal Dainton Harries, 14, also wore a skirt. He hopes the school will change its no shorts policy.
He said: "It's been way too hot in black trousers. We aren't breaking the rules wearing skirts. It was cooler wearing a skirt and I felt I could concentrate better. Most of the teachers told us they thought it was a good idea. I had Welsh literature GCSE and it was easier to work not being too hot. I have another science GCSE tomorrow and I'm wearing a skirt again."
Dainton's parents, Rhian and Kalam, said that when they asked the school if he could wear shorts they too were told no.
Rhian said: "They have a no shorts policy, even though we have asked for a flexible approach. They won't allow them to go in in their PE kit shorts and the poor kids are boiling.
"They borrowed skirts off girlfriends, but I would quite happily have gone out and bought Dainton a skirt to wear. He is doing GCSEs and couldn't concentrate because it's been so hot this week.
"He sat his Welsh literature exam today wearing a skirt. I am happy about that."
Dainton's dad, Kalam, urged schools to be more flexible about what all pupils could wear in hot weather. He said he didn't understand the reason not to allow PE shorts.
"I am glad my son has the confidence to do this. We rang the school about shorts and they said no. I support him in doing this," Kalam said.
But the move has caused debate online, with some arguing all students should respect their schools' rules.
Some suggested the children should become more resilient, despite the heatwave.
"A little bit of hot weather and they're moaning," one man said.
"Just wait until if any of you end up in a sweltering factory, shop floor, kitchen or somewhere else with ovens and heat, heat and more heat, then you will have to wear trousers as part of the uniform," another person added.
"Rules are important and should be obeyed," a further comment reads.
But others praised the boys for their stance, noting workplaces should also take heed.
One person said: "I think the schools and headteachers are completely out of order. Shorts should be part of the school uniform."
Another social media user shared: "Schools and workplaces need to get real. Shorts are perfectly acceptable."
A further person stated: "I do not see why there is such an issue with this. I do not see why the boys can not wear shorts so well done."
Headteacher of Ysgol Maes y Gwendraeth, Arwyn Thomas, said: “At Ysgol Maes Y Gwendraeth, as with most secondary schools across Carmarthenshire, we expect all our pupils to wear the formal school uniform. As a school community, we will continue to work together to monitor the situation and weather patterns carefully. If there are any changes, parents will be informed through our usual communication channels.”
Following our publication, Ysgol Bro Dinefwr says it has now changed its rules.
Headteacher of Ysgol Bro Dinefwr, Eirian Davies, said : "With the weather now warming we will be monitoring the situation in classes and across the school to ensure temperatures are comfortable for everyone. We have today allowed pupils the option of wearing their PE kit and will notify parents of any further changes in good time."
