There is a light on the Sound/Lighting Booth in the back of the Theatre that the Artists watch during Shows where weather may be a factor..
If it is Green,everything is cool.
If it turns Red,inclement weather is imminent and the show must stop.
The Artist has the option to finish the current song they are performing when the red light comes on.
And the "cut off" time to start the 8:00 show is 8:20.