These Guidelines help School leaders, teachers, and community members such as parents, understand the practical steps and considerations to plan and design the transformation of the schoolyard into a nature-based climate shelter. A nature-based Climate Shelter is a green space in the schoolyard, that can be opened to the community during extreme weather events such as heatwaves. Nature-based climate shelter offer a range of benefits for health, learning, social cohesion, and biodiversity. The advice provided is based on the experience of four case-study cities (Barcelona, Brussels, Paris, Rotterdam), where municipalities have undertaken the transformation of a large number of schoolyards as part of their climate resilience strategy.