Saint Mary is a small town located in Perry County, Missouri. It experiences a humid subtropical climate, characterized by hot summers and mild winters. Summers are typically warm and humid, with average temperatures ranging from the mid-80s to low 90s Fahrenheit. Winters are relatively mild, with temperatures usually in the mid-30s to mid-40s Fahrenheit.

The town is situated near the Mississippi River, which influences its hydrology constituents. The river provides a source of water for the town and supports various recreational activities. Fishing is a popular pastime, with anglers having the opportunity to catch a variety of fish species such as catfish, bass, and crappie.

In addition to fishing, Saint Mary offers various outdoor recreation opportunities. The nearby Perry County Community Lake provides opportunities for boating, swimming, and picnicking. The area also features numerous hiking trails and camping spots, allowing visitors to explore the beautiful natural scenery. Saint Mary is surrounded by picturesque forests and rolling hills, making it an ideal destination for nature lovers and outdoor enthusiasts.