This legislation requires the Under Secretary of Commerce for Oceans and Atmosphere to maintain the National Mesonet Program , designed to improve understanding and forecasting capabilities for atmospheric, drought, fire, and water events. The program emphasizes leveraging and integrating diverse environmental data from commercial, academic, and other non-Federal Government sources to enhance coordination across the U.S. weather enterprise. It aims to increase data density for the National Oceanic and Atmospheric Administration and the National Weather Service, supporting baseline forecasts, warnings, and hyperlocal predictions crucial for public safety and agriculture. Key objectives include improving boundary-layer data for numerical weather prediction, identifying gaps in air-sea interaction data, and helping achieve a 30-minute severe weather warning target. The program also mandates monitoring local meteorological conditions, such as soil moisture and road weather, to support operational forecasting and emergency management needs. To expand the mesonet system, the bill authorizes the Under Secretary to award at least 15 percent of annual appropriations as financial and technical assistance to State, Tribal, private, and academic entities for building or upgrading equipment. Recipients of this assistance must agree to provide data to the program and demonstrate sufficient non-Federal financial support for at least five years of maintenance, with priority given to remote or underrepresented areas. Furthermore, the legislation establishes an advisory committee of subject matter experts, including academic expertise, to recommend improvements and data acquisitions. The Under Secretary must provide annual briefings to Congress through 2035, detailing program activities and progress in addressing weather observation data gaps. The bill authorizes specific appropriations for the program, starting at $50,000,000 for fiscal year 2025 and increasing annually through 2029.