Cyclones originate in the deep sea, far away from land. Many of the sun's heat causes water to evaporate from the surface of the oceans, mixing with the atmosphere to increase the number of water vapor molecules. As a result, the density of air at sea level decreases and depression is created. Deep sea water temperatures and low sea pressure cause cyclones. The temperature of the sea water has to be above 27 ° C to create a cyclone .