Earth's climate varies dramatically along different lines of latitude from the equator to the poles. The explanation for this has to do with Earth's rotation (how long it takes to spin around one time on its axis; one day or 24 hours), its revolution (the amount of time it takes the Earth to complete one trip around the sun; one year or 365 days), and the tilt of our planet (23.5º). All three of these things affect the amount of solar energy different latitudes receive during different times of the year. Earth's tilt on its axis causes the seasons because as the Earth revolves around the Sun, different hemispheres and latitudinal areas of our planet are pointing towards or away from the sun. The following video explains the causes of Earth's seasons.


Climate and environmental conditions change with varying degrees of latitude, establishing latitudinal zones that share similar physical characteristics such as climate, vegetation, and biomes. Here are the geographic latitudinal zones of our globe, based on their location by latitude:

• equatorial (also known as tropical) zone
  
• subtropical zone
  
• mid-latitude zone
  
• subarctic (or sub-antarctic) zone
  
• arctic (or antarctic) zone
  

Zones in low latitudes are closer to the equator and high latitude zones are closer to the poles. The equatorial or tropical zone is located along the equator. The Tropic of Cancer, located at 23.5ºN latitude and the Tropic of Capricorn, located at 23.5ºS latitude mark the approximate boundary for areas that receive direct solar energy at noon. Therefore, the equatorial geographic zone extends from 23.5º N latitude to 23.5º S latitude. The arctic latitudinal zone extends from the Arctic Circle (located at 66.5º N) to the north pole (90º N), and the antarctic latitudinal zone extends from the Antarctic Circle (66.5º S) to the south pole (90º S). The arctic and antarctic geographic latitudinal zones are characterized by 24 hours of day during the summer and 24 hours of night during the winter.