Is it always very warm at the equator?

Answer 1

Climate is a very complicated subject, but in general, yes, it is usually warmer at the equator than at the tropics, which in turn are generally much warmer than the arctic and antarctic circles.

It's a bit more complicated than that, though, because the earth is tilted with respect to its orbit.

It all has to do with where the sun is directly overhead. In the northern winter, for example, the sun is directly overhead of the tropic of Capricorn (southern tropic), and so the light is more direct there, while at the tropic of Cancer (northern tropic) the light is coming in at a bit of an angle, making it less intense. This is further complicated because cooler air is denser than warmer air and will push warmer air up and away, and even worse, the earth is rotating. Warm air from where the sun is directly overhead can flow to where the sun is less intense, making it hotter there, while cooler air from less warm climes can flow into areas where the sun is directly overhead, significantly cooling things.