Schemes for dividing the Earth into climatic regions are based on a combination of indices of mean annual temperature, mean monthly temperature, annual precipitation totals and seasonality. The climate of a place is affected by several factors. Latitude affects the amount of solar radiation received, with the greatest in equatorial regions and the least in polar regions. Elevation affects both temperature and precipitation; mountainous areas are generally cooler and wetter. Location close to the sea or to large bodies of water moderates temperature; continental areas are generally more arid and more affected by extremes of temperature.