This guide aims to help World Bank task teams and development practitioners—as well as National Meteorological and Hydrological Services (NMHSs), which are, or may be, involved in working with national governments—to improve the delivery of national meteorological and hydrological services to their citizens and economies. It touches on all actors involved in the production and delivery of these services, with an emphasis on the role of the public sector. The guide provides insights into how to improve the skill, efficiency, and cost-effectiveness of publicly funded NMHSs so that they can carry out their mandate to protect lives, livelihoods, and property, and are able to support economic development.