Answer:
Temperature is simply a measure of energy present. The heating and cooling of the atmosphere cause currents as cold air moves towards warmer air.
Step-by-step explanation:
The most basic thing to understand is that warm air wants to rise while cold air wants to sink. Hot air contains fewer molecules per cubic meter while cold air contains more, hence the warm air will rise up over colder air. The most common example of this is the existence of a hot or cold front. These fronts are simply boundaries between hot and cold air.