For most people, a description of the weather is adequate but for many businesses more detailed and accurate measurements are required. The science of studying weather is called meteorology. This is important for giving people advance notice of severe weather such as floods and hurricanes . Temperature for example, is measured with a thermometer, usually containing mercury.
Temperature is the hotness or coldness of an object.
Rainfall is usually measured by collecting what falls in rain gauges. Rainfall is expressed as a depth of water that has fallen, in millimetres or inches. Wind can be simply observed with a weather vain. To measure its speed, more technical equipment is needed. Alternatively, the Beaufort scale can be used to make a judgment of the strength of the wind by observing how it affects objects outdoors like trees.