Vandalia, Missouri is a small town located in Audrain County in the central part of the state. The climate in Vandalia is classified as humid continental, characterized by hot and humid summers, and cold winters. Average temperatures range from the mid-80s°F (29°C) in summer to the mid-30s°F (2°C) in winter. Precipitation is evenly distributed throughout the year.

Vandalia is situated near the Salt River, which flows through the county. Hydrology constituents in the area include the Salt River itself, along with several creeks and streams that contribute to the local water system. These water bodies provide opportunities for fishing, boating, and other water-related activities.

Outdoor recreation in Vandalia is diverse, with several parks and natural areas offering opportunities for hiking, camping, and wildlife viewing. The nearby Mark Twain State Park, situated on the shores of Mark Twain Lake, is a popular destination for outdoor enthusiasts. The park features numerous hiking trails, picnic areas, and a marina for boating and fishing.

Overall, Vandalia, Missouri offers a pleasant climate, diverse hydrology constituents, and a range of outdoor recreation opportunities for residents and visitors alike.