Weather generally refers to day-to-day temperature and precipitation activity. Weather changes in four main ways: its movement, which can bring winds; its temperatures, which can cause anything from frost to heat waves; its moist content can bring rain and fog, and lastly its pressure can cause anything from cloudless days to fierce storms. The studying on how the weather works on other planets has been helpful in understanding how weather works on Earth. Weather is one of the fundamental processes that shape the Earth. Weather occurs due to density temperature and moisture differences between one place and another. These differences can occur due to the sun angle at any particular spot, which varies by latitude from the tropics. Common weather phenomena include wind, cloud, rain, snow, fog and dust storms. Less common events include natural disasters such as tornadoes, hurricanes, typhoons and ice storms. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location or area. Every three hours, 10,000 weather stations world-wide simultaneously record observations of weather conditions. The average weather in a particular area is known as ‘climate'. Weather has played a large and sometimes direct part in human history.