The typical weather observed in a particular place over a long period of time is said to be the climate in that location. Nearly all of the planets in the Solar System have atmospheres. Many of the larger satellites have atmospheres as well. For these planets, the atmosphere is considered to be the outermost layer of gases. The atmospheres of some planets and planetary satellites are very thin.
Scientists suspect that planets in other solar systems have atmospheres as well.
The search for such planets is currently a very hot astronomical topic. Each planet's atmosphere has its own unique composition. The atmospheric composition can help identify the host planet like a fingerprint. As mentioned earlier, atmospheres are composed primarily of heavy gases. Composition alone does not determine the properties of a planetary atmosphere.