Climate change is causing heatwaves to happen more often and become more intense around the world. This is creating serious problems, especially in cities where many people live close together. Higher temperatures, along with rapid urban growth and weak infrastructure, are making cities harder to live in. Buildings, roads, and vehicles trap heat, making urban areas much hotter than nearby rural places due to the Urban Heat Island Effect. This paper looks at the main reasons behind extreme heat, such as global warming and loss of green spaces. It also explains how heatwaves affect people’s health by causing dehydration, heatstroke, and even death in severe cases. In addition, high temperatures reduce work productivity and put pressure on electricity systems because of increased use of air conditioning. The paper also discusses possible solutions, like planting more trees, improving city planning, and using better building materials to reduce heat. It highlights the need for strong government action and public awareness. In conclusion, if steps are not taken soon, many cities could become too hot to live in safely, leading to serious problems for human survival and quality of life.