Rain Random

Hi. I'm kind of a noob when it comes to coding without the help of a youtube tutorial. so i've been trying to make a system when it will rain randomly and its has not been going so well. . .

 #pragma strict
 
 public var rainornot : int;
 private var myLight : ParticleEmitter;
 var myTimer : float = 10.0;
 
 function Start ()
 {
     audio.Play();
     myLight = GetComponent(ParticleEmitter);
 }
 
 function Update ()
 {
     if(Random.Range(1,40) == 2)
     {
         var rainornot = 1;
         
         if(myTimer <= 0)
         {
             var rainornot = 0;
         }
     }
     
     if(rainornot == 1)
     {
         myLight.enabled = !myLight.enabled;
     }
     
     if(myTimer > 0)
     {
         myTimer -= Time.deltaTime;
     }
 }