The difference between tropical and temperate climates is mainly the result of

There geographical location and rotation effect of earth on its axis.

Explanation:

As tropics are hot and humid regions in the earth they have an average temperature of about 65 degrees F and also being located closer to the equator they exist a variation in temperature. As the tropics receive most of the sunlight at an angle of 90 degrees. They separate themselves from the temperate regions that have cooler and calmer temperatures. As the rays of the sun are inclined toward the polar regions and so is the temperate region obliques rays. All these zones thus have a biomic realm that separate them from the others. Most of the rainforests and biodiversity are generally found in this layer only.  As tropics have high precipitation and high moisture content and temperature have, moderate climate and polar have extremely dry and cold weather.