McGrann, Pennsylvania is a small borough located in Armstrong County. The climate in McGrann is considered a humid continental climate, characterized by warm summers and cold winters. Summers are generally mild with temperatures ranging from the mid-70s to low 80s Fahrenheit, while winters can be quite cold with temperatures dropping into the 20s and occasionally below freezing.

The hydrology constituents in McGrann are primarily influenced by the nearby Allegheny River, which flows along the borough's western border. The river provides opportunities for recreational activities such as fishing, boating, and kayaking. Additionally, the area is also home to several smaller streams and ponds, offering further opportunities for outdoor water recreation.

Apart from water-based activities, McGrann and its surrounding areas also offer a variety of outdoor recreational opportunities. The region is known for its beautiful forests and rolling hills, making it ideal for activities like hiking, camping, and wildlife observation. There are numerous trails available for exploration, allowing visitors to immerse themselves in the natural beauty of the area.

Overall, McGrann, Pennsylvania presents a pleasant climate, diverse hydrology constituents, and abundant outdoor recreation opportunities, making it an attractive destination for nature enthusiasts and those seeking outdoor adventures.