What causes lightning?

Lightning happens in thunderstorms. It happens when liquid and ice particles above the freezing level collide and build up large electrical fields in the clouds. When electric charges get big enough, a giant "spark" happens between them, like static electricity, making the charge separation smaller. Lighting can happen between clouds, between the cloud and air, or between the cloud and the ground. The cloud-to-ground lightning usually occurs where the darkest clouds are and where the lighter and fuzzier clouds are. Sometimes, a lightning strike can strike outside of the storm miles away and seem like it came out of the clear blue sky. As long as a thunderstorm still has lightning, you know that it still has active updrafts and is still producing precipitation. The temperature of a lightning bolt can be up to 50,000 degrees F, hotter than the surface of the sun. Lightning can often catch trees on fire. Things that are struck by lightning can catch on fire, or show little or no evidence of burning at all.