What is Wind?

Wind is a bit of a mystery. We don’t see it, but we feel it. So what exactly is wind?

Wind is the movement of large amounts of air. Although we cannot see air, we know that it is made up of molecules of different gases, mainly nitrogen and oxygen. When many of these molecules move, usually in one direction, we call it wind.

Where does Wind come from?

Wind is created by pressure differences in the Earth’s atmosphere. Air from an area of high pressure moves to an area of low pressure. High winds are created when air moves between areas with large differences in atmospheric pressure.

On Earth, the main difference in atmospheric pressure is due to the difference in temperature. Cold air produces high air pressure and warm air produces low air pressure. Hot air wants to rise. As warm air rises, cool air enters and displaces warm air, creating wind.

Another factor that affects the wind is the rotation of the Earth. This is called the Coriolis effect.

How can we measure Wind?

Meteorologists use two main measurements to describe winds: direction and speed.

Wind Direction – Wind direction is described using the direction the wind is blowing from. For example, a southerly wind will blow from south to north. Wind direction is measured in several ways, including spoilers, flags, and windbreakers.

Wind Speed – Wind speed is measured in miles per hour or kilometers per hour. Scientists often use an instrument called an anemometer to measure wind speed.

Global Winds

Earth has consistent wind patterns when viewed globally. Global winds are produced by both the Earth’s rotation (the Coriolis effect) and the temperature difference between the equator and the polar regions. These winds are usually grouped as trade winds, easterly winds, and westerly winds.

Trade Winds – Trade winds occur near the equator and flow north or south towards the equator. They curve to the west due to the Earth’s rotation.

Prevailing Westerlies – At mid-latitudes of the Earth, from latitudes 35 to 65 degrees, we find prevailing westerly winds. These winds blow from west to east and also towards the poles.

Polar Easterlies – These winds blow near the north and south poles. They move away from the poles and bend from east to west.

Local Winds

Some winds are produced locally by changes in atmospheric pressure and temperature. These winds can change direction as conditions change throughout the day.

An example of a local wind is the wind that blows off the coast. During the day, the land heats up faster than the ocean. This causes a “sea breeze” blowing from the ocean to land. During the night, the land will cool faster than the ocean, and the opposite will happen. Warm air over the water will rise and cool air from the land, known as the “land wind,” will blow toward the ocean.

Land formations such as mountains, valleys, lakes and deserts can also influence local wind conditions.

Wind Power

Wind is an excellent source of renewable energy. Wind turbines and wind farms can generate electricity without burning fossil fuels or causing pollution. You can read more about this on our wind energy page.

Interesting Facts about Wind

The fastest winds on Earth occur inside tornadoes, where wind speeds can reach 250 miles per hour.

Meteorologists use barometers to measure atmospheric pressure. Barometers can tell us whether atmospheric pressure is decreasing or increasing.

Wind helped shape the land through the process of erosion.

All other planets with atmospheres have winds. Neptune has the fastest sustained winds in the solar system with wind speeds of 1,300 miles per hour.

The Solar Wind is a stream of charged particles blowing from the Sun.