On Earth, regularly happening weather phenomena include such things as wind, cloud, rain, snow, fog and dust storms. Less common events include natural disasters such as tornadoes, hurricanes and ice storms. Almost all standard weather phenomena on Earth occur in the troposphere. Weather does occur in the stratosphere and does affect weather lower down in the troposphere, but the exact mechanisms are poorly understood.
The Earth's atmosphere is one large chaotic system so small changes to one part can have large effects elsewhere. This makes it very difficult to exactly predict short term weather changes more than a few days in advance, though weather forecasters are continually working to extend this limit through the science of the study of weather, Meteorology. Chaos theory explains that there are an infinite number of variables which affect the weather. The slightest variation in the motion of any molecule in the air influences the atmospheric situation. The slightest difference could affect the troposphere sufficiently to lead to utterly different conditions. Thus it will never be possible to forecast perfectly