At least 350 pupils at Ndhiwa Hospital Primary School in Homa Bay County are studying under the hot sun after their classrooms were damaged in a windstorm at the weekend.
Pupils reported back to school on Monday morning and found five iron-sheet classrooms damaged.
The roofs of two classrooms were blown off, and the walls of the others were torn apart.
Teachers instructed pupils to set up their desks away from the damaged structures.
But because the school has no trees, the pupils had to learn under the hot sun.
This will be the norm for the next couple of days as the school waits for assistance to rebuild the classrooms.
School administrators warned that if the government and other organisations do not intervene, academic performance will be affected.
Headteacher Jefferson Onguti said they were shocked to find the damage on the day the school reopened for third term. Standard Eight pupils are making their final revisions ahead of the Kenya Certificate of Primary Education (KCPE) examination.
He said the school has been dilapidated for years and appeals to the government had been in vain.
"I have been in this school for five years. Very little development has taken place over the period I have worked here," Mr Onguti said.
The school has 13 teachers and 570 pupils, who learn in eight classrooms, five of which are made of iron sheets.
Pupils also share latrines with their teachers.
Mr Onguti said the damaged temporary structures were used by pupils from grades One to Five.
He said the condition of the classrooms made it difficult for pupils to learn, especially in hot weather.
The Ministry of Education recently began putting up a permanent classroom and construction is underway.
"We need more assistance in infrastructural development. We are ready to receive help from both the government and other humanitarian organisations," Mr Onguti said.
Deputy headteacher Saline Oyomo told journalists that the school records average performance in KCPE exams.
But she said she was worried that the current state of the school will undermine academic performance.
"We have to release pupils to go back home every time it is about to rain because they cannot stay in school during a downpour. This reduces the time pupils spend in school," she said.
Books used by pupils were also destroyed in the windstorm.
Stationery is usually kept in the staffroom, which was also damaged by wind and rain, Ms Oyomo.