What atmospheric force causes moving air to curve because Earth rotates?

The atmospheric force that causes moving air to curve because Earth rotates is the Coriolis effect. It does not push air from rest, but it changes the apparent direction of moving air relative to Earth’s rotating surface.

In the Northern Hemisphere, the effect deflects moving air to the right of its path. In the Southern Hemisphere, it deflects air to the left. The effect is zero at the equator and becomes stronger toward the poles, while faster-moving air experiences a larger deflection.

The Coriolis effect helps shape large weather systems, including cyclones and anticyclones. It makes Northern Hemisphere low-pressure systems rotate counterclockwise and Southern Hemisphere low-pressure systems rotate clockwise. It is not the primary cause of wind: pressure differences start the motion, and rotation bends the resulting flow.