Air evening things out
What Makes Wind Blow?
Uneven heating makes uneven pressure, and air always flows from high to low.
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Step 1 of 5
The Sun does not heat everywhere equally.
A sunny beach builds one every afternoon. That is the sea breeze. Dark soil warms faster than water. The equator gets more direct sun than the poles. Every difference in temperature makes a difference in pressure.
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Step 2 of 5
Warm air rises and thins out.
Heated air expands, becomes less dense and floats upward — leaving fewer molecules pressing down. That is a region of low pressure.
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Step 3 of 5
Air flows from high pressure to low.
Crowded air always pushes towards the emptier place. That flow is wind — and the bigger the pressure difference, the faster it moves.
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Step 4 of 5
The steeper the difference, the stronger the wind.
A gentle pressure gradient gives a breeze. A steep one — the kind around a deep storm — gives a gale.
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Step 5 of 5
Earth's spin bends the flow.
Air does not travel straight from high to low. Earth turning underneath deflects it, which is why weather systems spiral instead of collapsing inward.
Coastal sea breezes reverse at night: the land cools faster than the sea, so the flow turns around.
The short version
Every temperature difference becomes a pressure difference, and wind is crowded air pushing towards the emptier place — a breeze on a shallow gradient, a gale around a deep storm. Earth's spin bends the flow, so weather spirals instead of collapsing inward.
Try it yourself
Open a door between a warm and cold room and hold a tissue at the top, then the bottom. It blows opposite ways.