What kind of lunch is better to bring at noon? I am a student. Does the lunch go bad when the weather is hot?

If the weather is hot, it is best to pack the box lunch before eating (it is not easy to deteriorate after eating), and put it in the refrigerator when it is cold. If there is no refrigerator, put it in a ventilated place and don't touch it after installation. There is generally no microwave oven to heat meals at school, right? Just take out the food, heat it and put it in a thermos before school. If the weather is hot, the food won't be cold at noon.