Keystone, Iowa is a small town located in Benton County. It experiences a humid continental climate, characterized by warm summers and cold winters. The average high temperature in summer reaches around 80°F (27°C), while in winter, it drops to around 32°F (0°C). Precipitation is fairly evenly distributed throughout the year, with an average of 35 inches annually.

Hydrologically, Keystone is situated near several water bodies, including the Cedar River and Otter Creek. These water sources provide opportunities for fishing, boating, and other water activities. Additionally, there are several parks and green spaces in and around Keystone that offer outdoor recreation opportunities. For instance, Pleasant Creek State Recreation Area, located just north of Keystone, is a popular spot for hiking, camping, swimming, and picnicking.

Overall, Keystone, Iowa offers a pleasant climate for outdoor activities, with ample opportunities for water-based recreation and access to nearby parks for various outdoor pursuits.