On this answer, I will be helping you regarding which season line thunderstorms occur for your school projects.

Line thunderstorms, also known as squall lines, are most common during spring and summer in South Africa. Think about the hot, humid summer months in places like Gauteng or KwaZulu-Natal. This heat causes the air to rise rapidly, leading to the formation of thunderstorms.

These storms often occur during late summer when the air is warm and moist, creating the perfect conditions for intense weather systems, including line thunderstorms.