Mosby, Virginia is a small unincorporated community located in Fauquier County. Its climate is characterized as humid subtropical, with warm summers and mild winters. Summers in Mosby tend to be hot and humid, with average temperatures ranging from the mid-70s to mid-80s Fahrenheit. Winters are generally mild, with average temperatures in the mid-30s to mid-40s Fahrenheit.

Hydrologically, Mosby is not situated near any major bodies of water. Instead, it is surrounded by rolling hills and farmland typical of the Piedmont region of Virginia. The area is primarily drained by small creeks and streams that flow into the nearby Chesapeake Bay watershed.

For outdoor recreation opportunities, Mosby offers a tranquil natural setting that is ideal for activities such as hiking, cycling, and bird-watching. The area is dotted with scenic trails and picturesque rural roads, making it perfect for exploring the countryside. Nearby parks and nature reserves, such as the Manassas National Battlefield Park and the Bull Run Mountains Conservancy, provide additional options for outdoor enthusiasts. Mosby's close proximity to the Blue Ridge Mountains also offers opportunities for more adventurous activities like camping and fishing in the region's rivers and streams. Overall, the community of Mosby offers a peaceful and scenic environment for outdoor recreation.