What are weather reports?

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Weather forecast map

Weather reports vary a lot in how much information they contain. The simplest and shortest weather report contains only one piece of information: the present temperature. This is the type of report you often hear on the radio. More detailed weather reports also contain information about precipitation, wind speed and direction, relative humidity, atmospheric pressure, and other things as well.

A typical weather report tells you the high and low temperatures for the past day. It also tells you the present temperature. It might tell you the average temperature for the day, which lies halfway between the highest temperature and the lowest temperature. To find the average temperature, add the low temperature and the high temperature and then divide by two. The weather report might also tell you how many degrees the average temperature is above or below the normal temperature for that day. The normal temperature is found by adding up the average temperatures for that calendar day over a long period, like fifty years or a hundred years, and dividing by the number of years. In many areas of the United States, unusually hot or cold days can be as much as twenty degrees different from the normal temperature.