How far up do clouds go?

Question

and if you go far enough in the sky when its thunderstorms etc, is it clear?

Answer 1

Clouds can go upto the tropopause only.Above that, the temperature increases and the atmosphere becomes stable.So, convection can not take place to produce clouds.Occasionally, the top of cumulonimbus cloud may pierce the tropopause due to strong updrafts.

Answer 2

Yeah its clear above thunderstorms, and the highest clouds are only a few miles high.

Answer 3

Clouds in the troposphere (the lowest layer of the atmosphere) can build as high as over 70,000 feet (usually in the tropics), but typically build to about 50,000 feet at the top of thunderstorms in the mid-latitudes.  Even higher are the noctilucent clouds, but they form from a different mechanism.