Weather is the state of the atmosphere from day to day. It includes temperature, atmospheric pressure, clouds, wind, and precipitation. Climate is the long-term average of the weather. It is observed over periods of many years, decades, and centuries. In many areas of the United States, the daily high temperature or the daily low temperature can vary by as much as 30 degrees F from day to day. In contrast, the average temperature for a whole year seldom varies by more than one degree.