What makes the wind change direction?

Answer 1

The wind changes direction based on the Earth's rotation and areas of high and low pressure. Winds circulate around areas of pressure and these areas of pressure are constantly moving. As they pass over an area, the direction the wind is coming from will change.

Answer 2

According to the Wikipedia wind speed article, wind direction and speed are affected by three (3) main factors:

1. Pressure Gradient - the difference in barometric pressure between adjacent zones of high and low pressure.

2. Frictional Forces - features on the Earth's surface which oppose the wind; e.g.: mountains, trees, buildings, etc.

3. Coriolis Effect - the Earth's rotation causes winds to be deflected to the right in the Northern Hemisphere, and in the Southern Hemisphere to the left.

The driving force (1 - the pressure gradient) is due mostly to temperature differences in air caused by sunlight (at least for winds that we feel on the ground). As the sun shines on the earth, it heats the air differently in some areas than others. For example, a lake absorbs heat from sunlight differently than a forest or a parking lot. If the air in an area is warmed, it's pressure is increased, and it pushes out into areas of lower pressure - causing wind.

Ever wonder why it's so windy at the beach? Factors 1 and 2 are at work - there are pressure differences caused by sunlight hitting the water and water currents heating or cooling the air on the ocean surface. There are also no hills, trees or buildings to oppose or slow down the wind, so even winds generated far from shore can still reach you.

Answer 3

wind speed changes because when it goes up a hill or down a hill or over a valley the height and temperature drop or increase and it speeds up the wind and then when it levels out again from the bottom of the hill it slowly goes back to how it was from lots of little ups and downs in the shape of the earth.

Answer 4

pressure