Earth's climate is determined by the amount of incoming solar radiation that reaches the planet and the amount of reflected heat energy that radiates back into space. There are also a number of lesser factors that affect the average weather conditions that compose the various regional climates found across the globe.
Earth's climate is a complex system created by interactions and energy transfer between the planet's atmosphere and the various landmasses and bodies of water that make up its surface. The planetary climate has evolved under the influence of its own internal dynamics and variations in solar output. Even human industry has played a role in shaping the climate, as it has been responsible for shifting the density of certain atmospheric gases that are able to trap heat that would otherwise radiate back into space.
Area climates can differ greatly from region to region depending on any number of factors. For example, polar and equatorial regions experience vastly different climates due to their locations and the amount of solar energy that they receive and absorb. Differences in elevation, composition of landmasses and the influence of prevailing wind patterns all play a role in determining the average weather patterns that comprise regional climates.