The first scientific records of weather and climate in the western United States were collected during the Lewis and Clark Expedition of 1803 to 1806 as they traversed uncharted territory between St. Louis, Missouri and the Pacific Ocean. Various expedition members recorded daily weather observations and information on climatic regimes through detailed descriptions of flora and fauna in the Narrative Journals. In addition, Lewis and Clark kept a separate Weather Diary with daily observations of temperature, wind, weather conditions, and river levels. A recently released American Meteorological Society Historical Monograph, edited by the presenter and the AMS, provides a comprehensive summary of the data collection and weather-related challenges that threatened their safety and nearly derailed the Corps of Discovery's mission. "Lewis and Clark" is a compelling read for weather and history buffs, and a key resource for scientists researching climate history. An overview of journal findings and significant weather events during the Expedition will be presented.