Hi Doug,
Without seeing the tree, I can guess that the wet spring and humid weather have caused a needlcast infection in your blue spruce. This fungal infection is common in Colorado blue spruce as it is adept at growing in a much drier climate than ours. 
You can read more about needlecast, and compare the symptoms with what you are seeing using the link below. 
https://extension.umn.edu/plant-diseases/rhizosphaera-needle-cast

If you have any questions, please feel free to reach out. 

Thank you,
-Julie