A front is the leading edge of a moving mass of uniformly cool or warm air.
Under stable conditions, a mass, or area, of air will take on common characteristics of temperature, humidity, and pressure. The mass then moves as a unit according to the general circulation patterns around the world.
Different masses move at different speeds. Fronts are where two masses catch up or run into each other.
Based on the properties of temperature, humidity, and pressure, the clashing fronts create relatively standard weather patterns.
Earth has certain predictable patterns of winds called prevailing winds. The air temperature at the equator is warmer than the air north and south of it. This difference in temperature is a major cause of Earth’s global winds.