airspace classes C-G no relation aeronautical meteorology
Visibility and separation from clouds
With good visibility, pilots can determine the aircraft attitude by utilising visual cues from outside the aircraft, most significantly the horizon. Without such external visual cues, pilots may be subject to sensory illusions and must use an alternative reference for the attitude, which is usually provided by gyroscopically-driven instruments such as the attitude indicator ("artificial horizon"). The availability of a good horizon cue is controlled by meteorological visibility, hence minimum visibility limits feature in the VMC minima. 
Because the basic traffic avoidance principle of flying under visual flight rules (VFR) is to "see and avoid", it follows that distance from clouds is an important factor in the VMC minima: as aircraft flying in clouds cannot be seen, a buffer zone from clouds established by the minimum separation requirements provides for time to react to an unseen/unknown aircraft exiting the clouds, especially when air traffic control may not be enforcing aircraft separation (as in airspace classes C-G).
no relation