Blue Hill Observatory & Science Center's mission is to foster public understanding of Earth’s weather, climate, and environmental systems and to continue to produce, maintain, and analyze a meticulous, consistent record of weather and climate observations. We envision a world where the health and well-being of all people and the planet are protected and promoted through Earth system science research, education, and outreach. The Blue Hill Meteorological Observatory, located atop of Great Blue Hill just south of Boston, is a unique American institution. Founded in 1885 by Abbott Lawrence Rotch, one of the most respected scientists of his time, the Observatory was established as a scientific center for the measurement and study of the atmosphere, and it became the site of many pioneering weather experiments and discoveries. Rotch made his first weather observations on February 1, 1885, and ever since that date an unbroken climate record has been maintained. This remarkable resource, which is the most homogeneous climate record in North America, is considered a benchmark for climatology and the study of climate change in the U.S. Northeast, leading the World Meteorological Organization to recognize the Observatory as a Centennial Climate Station. The Observatory is also a recognized National Historic Landmark. Generations of meteorologists received their training at Blue Hill Observatory. Important research studies on atmospheric radiation, clouds, and rainfall patterns were conducted on the Hill, and many meteorological firsts, including atmospheric research with kites and the development of the radiosonde (weather balloon), also occurred at this historic site. Our daily weather observation and data collection for 139 years form the longest, most consistent, and most extensive climate record in North America—and they are an irreplaceable resource that supports the Observatory’s mission to advance climate research and understanding.