This activity involves the development of a “A guidance note for including citizen science in weather, climate and water projects”. The note outlines the definition of citizen science, provides a typology of Citizen Science projects, and illustrates examples of different types of citizen science projects. The note also raises guide questions for project managers of citizen sciences projects. The guidance note is available for download from the WMO library at https://library.wmo.int/records/item/57657-high-impact-weather-hiweather-citizen-science-guidance-wwrp-2021-2