This is a good discussion. As an Air Force pilot, here are the requirements for circling...

"If a circling approach is to be flown, the weather must be at or above both the published ceiling and visibility. Circling to land is a visual flight maneuver. When the instrument approach is completed, it is used to align the aircraft with the landing runway. After descending to circling minimum descent altitude and when the airport environment is in sight, determine if the ceiling and visibility are sufficient for performing the circling maneuver. The airport environment is considered the runways, its lights and markings, taxiways, hangars, and other buildings associated with the airport."
Air Force Manual 11-217Vol1

So as long as the WX (ceiling and vis) is at or above the mins, I can shoot the approach, and as long as I can keep the airport environment in sight, I can descend below MDA to intercept a normal glide path for landing. So the way I was taught, I don't need VMC conditions (1500/3 for USAF).

Thread post alibi...Please don't blast me for posting USAF criteria. LOL! Just wanted to contribute to the discussion.