Due to ongoing climate change, hot waves (heat waves) are occurring more frequently, negatively affecting the human body. Urban residents experience these effects particu-larly severely, as built-up areas contribute to the formation of so-called urban heat islands. This phenomenon primarily results from the development of green spaces and the reduction of seminatural surfaces, leading to intensified city heating and hindering natural cooling processes. This article discusses the heat balance of solar radiation and the impact of elevated temperatures on the human body. It also presents the mecha-nisms behind urban heat island formation and strategies for mitigating their effects. One of the key solutions is the implementation of Green Infrastructure, which includes trees, parks, gardens, and green roofs. Such measures help lower air temperatures, improve thermal comfort for residents, and minimize the adverse effects of prolonged heatwaves. The role of greenery in cities is particularly important during periods of high temperature and humidity. Vegetation acts as a natural climate regulator by providing shade, increasing humidity, and reducing surface heating. Therefore, it is crucial to incorporate strategies into urban planning that maximize the potential of Green Infrastructure. This article examines selected aspects of Green Infrastructure implementation in cities, highlighting its significance in mitigating the effects of cli-mate change and enhancing the life for residents.