The Lewis and Clark Expedition (1803-06) systematically recorded weather and climate data during their 4,162-mile journey through what is now the western portion of the USA. Lewis and Clark collects all such data from their various journals, describes the importance of this first-of-its-kind meteorological undertaking, and includes a colour pictorial of the Lewis and Clark Trail. It will serve as a compelling resource for weather, history, and Lewis and Clark buffs alike, as well as for scientists looking back at weather and climate in the early 1800s.