Weather differs every day due to changes in heat, wind and moisture. The revolution of Earth around the sun is the primary reason for seasonal changes.
Weather refers to the condition of Earth's atmosphere at any given time, and includes temperature, air pressure, precipitation and cloud cover. Low pressure typically causes precipitation and cloudy weather, whereas high pressure usually results in fair weather.
Land masses and bodies of water receive irregular amounts of the sun’s rays due to Earth’s round shape. Regions near the equator experience more warmth than other places because they get more direct sunlight. In contrast, the polar regions experience colder temperatures, as they receive almost no sunlight during winter. These temperature differences result in constant air and water movements, which distribute the sun’s heat energy across Earth and cause ocean currents and jet streams. The uneven heating and cooling of various places on the planet cause winds. Clouds are pushed by winds, and they bring moisture that turns into rain or snow.
The atmosphere in a particular area becomes less dense and starts to rise when it becomes hotter than the surrounding air. As colder, denser air falls in other regions and pushes air outward, the air travels on the surface, thus completing the cycle.