The equator is parallel to the suns rays. So these rays are more harsh towards the equator. This is why it is hotter the closer you are to the equator. However, The sun rays get bend as it gets farther north or south of the equator so it isn't as harsh and the sun can't warm these areas as easily causing it to be colder. This concept is also why it stays dark in the north and south for extremely long periods of time.
