United States Climate Data

Northern Sierra Nevada's Lovers Leap at Giant Gap American River Gorge

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U.S. Color Satellite

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NE Pacific Satellite

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Local Area Radar

Northern California Nexrad Doppler Radar

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Local WX Conditions

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Alta, Ca. Fire Danger

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U.S. Climate Information

Climate vs. Weather ( What to expect vs. What is happening )

Climate is the expected state of weather variable such as precipitation or temperature. Climate values are defined as averages of weather variables over time periods such as 30 years. For example, the monthly mean temperature for December is a climate variable. This value is computed using observered temperatures in December over a time period of 30 years.

Weather is the state of the atmosphere at a given moment in time. An example would be the air temperature on January 1, 2006. Over time, the individual weather values are incorporated into the climate values as they are averaged into the long-term value.

A climate forecast provides information on how close the coming monthly values are expected to compare to the long term values for large spatial areas. A weather forecast is much more specific in that it provides information on temperature, precipitation, wind, etc. for the next several days at given locations.