Why Do Rain Clouds Produce Lightning While Normal Clouds Don’t?

[Protonic]

Why doesn't it lightning on a cloudy day? I mean lightnings when there are rain clouds but normal clouds on a sunny day don't yeild lightning. Is it rainwater's conductivity?

 

[cjl]

It depends on the type of clouds. Different clouds have vastly differing properties, and the majority of them simply don't build up enough charge. It takes a fairly large and violent cloud to build up enough charge to cause lightning, and most of these types of clouds also cause rain.

 

[K^2]

Rain carries the charge between cloud and ground, allowing the clouds to become charged. So yes, rain is instrumental in causing lightning.

You can have lightning without rain in some rare situations. When air is sufficiently dry and warm at low altitude, you can have rain drops that evaporate before they reach the ground. In that case, the charge is carried between two clouds, and you can see lightning between these clouds without there being any rain at ground level. But it still has to be raining up there.

 

[Protonic]

Rain carries the charge between cloud and ground[b/], allowing the clouds to become charged. So yes, rain is instrumental in causing lightning.

You can have lightning without rain in some rare situations. When air is sufficiently dry and warm at low altitude, you can have rain drops that evaporate before they reach the ground. In that case, the charge is carried between two clouds, and you can see lightning between these clouds without there being any rain at ground level. But it still has to be raining up there.

U mean the charge going up into the cloud or the lightning itself?

 

[K^2]

Before you can get lightning, the cloud must be charged relative to ground. To get that, you must have charge flow from cloud to ground. Rain allows for that.

 

[JaredJames]

What about collisions between ice particles in the clouds?

Like a giant static charge, no charge flow between cloud and ground necessary.