What determines wind speed

At the Earth's surface, wind blows horizontally from high pressure to low pressure areas. The speed is determined by the rate of air pressure change, or gradient, between the two pressure areas. The greater the pressure difference, the faster the winds.

Explanation:

Basically

At the Earth's surface, wind blows horizontally from high pressure to low pressure areas. The speed is determined by the rate of air pressure change, or gradient, between the two pressure areas. The greater the pressure difference, the faster the winds.