Martelle, Iowa is a small town located in Jones County in the eastern part of the state. The climate in Martelle is considered to be continental, with hot summers and cold winters. Average temperatures range from around 20°F (-6°C) in winter to 85°F (29°C) in summer. Precipitation is evenly distributed throughout the year, with an average of 34 inches (86 cm) annually.

The hydrology constituents of Martelle are primarily influenced by the nearby Wapsipinicon River. The river serves as a major water source for the town, providing opportunities for various recreational activities such as fishing, boating, and kayaking. The river is home to a variety of fish species, including catfish, bass, and northern pike.

In addition to the river, Martelle offers several outdoor recreation opportunities. The town has a number of parks and trails, including the Wapsipinicon State Park, which offers camping, hiking, and picnicking facilities. The nearby Martelle Nature Preserve provides a natural habitat for wildlife and is ideal for bird-watching and nature walks. Overall, Martelle provides a suitable environment for outdoor enthusiasts to enjoy various activities surrounded by the beauty of nature.