Answer:
Temperature is the kinetic energy of the particles of a substance.
Step-by-step explanation:
The more kinetic energy a particle has the higher it's temperature. In the case of the atmosphere, which is what we are primarily concerned with in Meteorology, we measure this using a mercury thermometer (in certain situations we use an alcohol thermometer and of course modern times have given us things like dewcells and digital thermometers but we always go back to the mercury thermometer for accuracy).