Marathon, Iowa is a small town located in Buena Vista County, in the northwestern part of the state. The town experiences a humid continental climate, characterized by hot summers and cold winters. Summers in Marathon are relatively warm, with average temperatures ranging from the high 70s to low 80s Fahrenheit, while winters are cold with average temperatures in the 20s to 30s Fahrenheit. Precipitation is evenly distributed throughout the year, with the highest levels occurring during the summer months.

In terms of hydrology, Marathon is situated near the Little Sioux River, which flows through the area. This river provides abundant opportunities for outdoor recreation such as fishing, boating, and kayaking. The surrounding region also boasts several lakes and ponds that offer additional water-based activities.

Furthermore, Marathon is surrounded by picturesque natural landscapes, making it a great destination for hiking, camping, and birdwatching. The nearby Koser Spring Lake Park offers scenic trails and picnic areas, while the nearby Little Sioux Wildlife Management Area provides opportunities for hunting, wildlife observation, and photography.

Overall, Marathon, Iowa offers both natural beauty and recreational activities for outdoor enthusiasts to enjoy throughout the year.