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clouds, rain, and snow form. Weather forecasters use the term “relative humidity,” referring to the percentage of water that air can hold at any given temperature. At 100 percent, air is saturated and cannot hold any additional water vapor. Any excess water above 100 percent becomes rain. Warm air can hold more moisture than cold air, which is why places near the equator are much more humid. For example, Singapore experiences year-round humidity because the air is highly saturated with water from the nearby Indian Ocean. Cloud cover: There are several kinds of clouds, and not all produce rain. Cirrus clouds are wispy and usually indicate mild weather. Nimbostratus clouds produce steady rain, while cumulonimbus thunderhead clouds are known for producing heavy rains, thunderstorms, and even tornadoes. Clouds affect how much sunlight can reach earth. On very cloudy days, clouds prevent more of the sun’s radiation from reaching the earth, which explains why cloudy days are often cooler than clear, cloudless days. Cloud cover at night acts like a blanket to keep the earth’s surface warm. Weather and Climate Based on these six components, you can see that weather is ever changing and ever moving. Weather is a temporary condition in the atmosphere influenced by these six components. Weather is different in your part of the world from how it is in another part of the world at any given time, but weather where you are will eventually affect the weather thousands of miles away. For example, a hurricane that makes landfall in Florida can eventually bring heavy rain and wind to the entire east coast of the United States. Regions of the world tend to have the same weather over time. On the Texas Gulf Coast, summers are always hot and humid. In Siberia, winters are extremely cold and harsh. Over many years, certain regions of the world are characterized by certain conditions. The average weather in a particular region is called climate . What is your hometown like?

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The Fundamentals of Weather

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