Winter At Spinney Mountain State Park Spinney Mountain State Park is closed each year from ice-on until ice-off, approximately November 15th to April 15th.
The only portions of the park that remain accessible during the winter are located along the South Platte River, either down stream of the dam or upstream of the reservoir. These two small sections remain open for fly-fishing during the winter and are walk-in areas only. Please observe the “Closed to all Public Use” signs that mark the boundaries of the closed areas. Trespassers will be prosecuted.