1.
Temperature - As the earth's surface is warmed by the sun, that heat radiates in to the atmosphere and warms it, too.
2. Air Pressure - Warm air is lighter than cool air, and it doesn't press as hard. Warm air rises, causing a low pressure area and usually clouds as well. Cool air sinks, causing a high-pressure area and usually sunshine.
3. Moisture - Moisture evaporates from oceans, rivers, and lakes and enters the atmosphere as water vapor. (We call the amount of water vapor in the atmosphere humidity.) As moist air cools, some water vapor condenses into tiny water droplets, forms clouds, and may fall as rain.
4. Wind - Cool, heavy air tends to move into warmer, low pressure areas. The warm, light air is forced to move upwards. This moving air is called wind. Changing the balance of these four basic ingredients can cook up some spicy weather!
