Climate change, driven by greenhouse gas emissions, poses a significant threat to human life and livelihoods. Africa, particularly vulnerable despite minimal contributions to global emissions, experiences extreme weather events like floods and droughts, leading to displacement, food insecurity, and loss of life. While climate change awareness is growing globally, understanding young people’s knowledge and perception of climate change in Africa is critical and has not been well elucidated. This study investigated the knowledge and perceptions of climate change among youth participants at the 3rd cohort of Nairobi Summer School for Climate Justice 2024. A mixed method, cross-sectional survey, and Focused Group Discussion (FGD) of 71 youth respondents drawn from 40 countries in Africa and Asia. The questionnaire surveys and FGDs were conducted to gather data on participants' knowledge and perception of climate change in their countries. Majority of respondents (36%) defined climate change as changes in weather and climate patterns. Seventeen percent attributed it to atmospheric changes, while 12% linked it to human-induced activities. Eleven percent noted that environmental impacts had led to climate change, and 9% believed it was associated with global warming. Only 7% defined climate change as averageweather conditions. 40% of respondents said climate change has an impact on human health, with 24% specifically mentioning mental health. 23% believed that environmental changes happen due to climate change. 10% attributed climate change's impact to economic and livelihood dynamics, indicating the critical role of environmental factors and social determinants of health in exacerbating climate change's health effects. Only 2% perceived the healthcare system as being insufficiently resilient to address and mitigate climate-related health impacts. The result of this study provides a foundational knowledge base that is essential for developing effective strategies to adapt and adjust to the challenges posed by climate change. It will further enable adoption of adaptation and adjustment strategies to combat the health effects of climate change through community ownership. By examining the knowledge and perceptions of this specific group of young climate activists who attended the Nairobi Summer School for Climate Justice (NSSCJ), this study aims to contribute to the development of effective climate change education and adaptation interventions, particularly for vulnerable populations. The study noted that it is imperative to improve public awareness of the connection between climate change and health, especially among vulnerable populations, to effectively increase public understanding and awareness. To mitigate the health impacts of climate change, the study recommends strengthening policies at all levels to raise public awareness and build capacity. Integrating climate change into public health curricula and practice is crucial to prepare healthcare professionals to address emerging health challenges.