Well, the earth is separated into two hemispheres, the northern and southern. The earth's axis is slanted, so as the earth rotates, it also turns (if that makes any sense), and as this happens there's always one side that's pointed closer to the sun. As one side is closer to the sun, it is summer for hemisphere, and the side pointed away has winter. That's why when it's winter in the US, it's summer in Australia. Furthermore, some countries are deserts. This doesn't only apply to countries however as there are deserts within countries too. Examples include Egypt, the entire country is a desert, where as Texas and Arizona are both states, but they are deserts too. These examples are all known as non-polar deserts, for not all deserts are heat and sand. An example of this is Antarctica. It's a polar desert, and it's the biggest desert in the world, the coldest desert in the world, and the driest place on earth. Anyways, there are many things that make a place hot. The climate, season, etc... And you know what they say, "It's not the heat that gets you, it's the humidity."