Nature · Earth Science
The ever-changing sky above us
Weather is the state of the atmosphere at a given moment — the rain, sun, wind and temperature of the day. Climate is the average of that weather over decades. Both are driven by the Sun heating the Earth unevenly and the endless movement of air and water that tries to even it out.
The Sun heats the tropics more than the poles, setting air and oceans in motion to redistribute that heat. Rising warm air, sinking cool air, the planet's spin and the water cycle together create winds, clouds, storms and the great climate belts that circle the globe.
From the weather-filled troposphere up through the stratosphere, mesosphere and beyond — the layers of air that wrap the Earth.
Where warm and cold air collide
Vast masses of warm or cold air sweep across the globe. Where they meet, the boundary — a front — lifts air to form the clouds and rain of everyday weather.
Earth's most powerful storms
Over warm tropical seas, rising moist air organises into a giant spinning storm with a calm eye at its centre — capable of devastating coasts with wind and flood.
Towering clouds of lightning and rain
When warm, moist air rockets upward, it builds anvil-topped storm clouds crackling with lightning, unleashing downpours, hail and sometimes violent tornadoes.
The great belts of world climate
Averaged over decades, weather settles into broad belts — tropical, arid, temperate, cold and polar — that determine the plants, animals and people of each region.