Who was the summertime navigational aid for Lewis and Clark expedition?

The summertime navigational aid for the Lewis and Clark expedition was a Shoshone woman named Sacagawea. She served as an interpreter and guide, helping the explorers communicate with various Native American tribes and navigate the rugged terrain of the western United States. Her knowledge of the land and languages was crucial to the success of the expedition. Sacagawea's contributions were vital in ensuring the safety and progress of the journey.