The most influential factor affecting weather in the atmosphere is heat. But where does this heat come from? A small amount of heat is generated from the Earth itself. This heat comes from a wide variety of sources, including hot springs, volcanic eruptions, radiation, and occasional forest fires. However, none of these sources produce heat on a large scale. Even a volcanic eruption is only hot enough to warm a very small area for a very short period of time.
The vast majority of heat found in our atmosphere comes from the Sun. Through the process of nuclear fusion, the Sun produces a massive amount of energy every moment of every day. In one second, the Sun produces more energy than mankind has ever used in our entire history.
Fortunately, most of that energy is radiated outward into the furthest reaches of the Solar System. If it was all focused on the Earth, what do you think would happen? Have you ever used a magnifying glass to focus sunlight onto a piece of wood? What happened? If you waited long enough, the wood probably began to smoke, leaving a black mark behind. Because only a very small portion of the Sun’s energy is intercepted by the Earth, we do not get over heated.