botanical garden - a facility where trees and shrubs are cultivated for exhibition. arboretum. facility, installation - a building or place that provides a particular service or is used for a particular industry; the assembly plant is an enormous facility.
Keystone, CO Weather. The average temperature of Keystone is 35.80Â°F, which is much lower than the Colorado average temperature of 46.26Â°F and is much lower than the national average temperature of 54.45Â°F. Historical Weather.
1 The lowest monthly average temperature in Keystone for December is 14 degrees. 2  The most monthly precipitation in Keystone occurs in January with 0 inches. 3  The air quality index in Keystone is 15% better than the national average.  The pollution index in Keystone is 85% better than the national average.