Isobars can be used to see the change of pressure in an area. This change is called pressure gradient, and is directly related to the speed of wind. The pressure gradient results in a net force from high pressure centers to low pressure centers.

When isobars are very close to eachother, the pressure gradient is steeper and winds are stronger.	When isobars are far away from eachother, the pressure gradient force is weaker and so are the winds.

Isobars are lines on weather maps which show pressure areas. See also: Isobars