In lightroom 6 I use the graduated filter tool and apply colour to skies, now having migrated to CC the linear Grad filter only changes exposure, temp etc but no colour option it seems, is this correct or is the colour option hidden away in preferences somewhere.
The Color option's missing at this point in time, so you'd need to put in a feature request at Lightroom CC | Photoshop Family Customer Community
You can tweak color using Temp & Tint though - that might get you closer.
The color option is not available in Linear gradient in Lightroom CC, In the spirit of the Lightroom tradition, if you find that aspects of Lr don’t meet your needs, just let us know & we’ll build it together. You may suggest it as a feature on this link:
Feature Request/Bug Report Form