June 11 - Coriolis effect

Coriolis effect - the apparent deflection of objects from a straight path if the objects are viewed from a rotating frame of reference. The most notable example is the deflection of winds moving along the surface of the Earth to the right of the direction of travel in the Northern hemisphere and to the left of the direction of travel in the Southern hemisphere. This effect is caused by the rotation of the Earth, and is responsible for the direction of the rotation of hurricanes and cyclones. As a consequence, winds around the center of a cyclone rotate counterclockwise on the northern hemisphere and clockwise on the southern hemisphere.

Hurricane Season - The hurricane and cyclone seasons officially began on June 1 and end on November 30. All storms in the Northern Hemisphere rotate counter-clockwise due to the Coriolis effect.