It depends.
If you're using SkyView's internal flight planning, and the waypoint causing a turn is set to not overfly (which is the default), then it calculates when a standard-rate turn would need to start to meet the next leg, based on your current GPS speed. This isn't adjustable.
If you're following a flight plan from an external device, it follows its magenta line, subject to autopilot limitations such as bank angle limitations you may have set.