Unity 5.0.2 - How can I know when a scene is loaded AND when it's running well?

Hey everyone,

I'm currently stuck on a QoL feature for a game I'm making.

Currently, I have a scene where players can join the game (up to four of them) and choose which character they want to play. Upon starting, the next scene begins to load. Once it's finished loading, I have the player press 'start' again, and the next scene is allowed to activate.

However, when the next scene comes up, it's always laggy at first and takes a few seconds to get going at full speed.

I'd like to figure out a way around this. My current plan is either to hide the level for a few seconds until it hits a consistent frame rate, but I want to know if there's a different, built-in way of detecting when a level is not only loaded, but when it's comfortable to play (running well).