Why is temperature relatively uniform throughout the year in the tropics along the equator?

The temperature is relatively uniform throughout the year in the tropics along the equator because of the variation of the net radiation of the sun in that area. At daytime, the sun warms the Earth and, at night, the heat is radiated back to space. The balance of these is the net radiation. At the equator, this value is almost always positive which means there would be more heat than being lost.

Americans often speak of their country as one of several large regions.  these regions are cultural units rather than governmental units --  formed by history and geography and shaped by the economics, literature and folkways that all the parts of a region share. what makes one region different from another? a region's multicultural heritage as well as distinct demographic characteristics like age and occupation make regions different and special. within several regions, language is used differently and there are strong dialects. there are also differences in outlook and attitude based on geography.