Depends on how the blades are angled. In winter, you want it to blow the warm air off the ceiling, to the floor. In summer, you want it to pull the cool air upwards.
Ceiling fan blades should turn counterclockwise in the summer to create a wind-chill effect that helps to cool the room. This motion pushes cool air down and creates a breeze.
Counter Clockwise. Push air down (down position on most fans)
Stand directly under the fan and observe the direction the blades are moving. If the fan blades are moving in a clockwise direction, the fan is set to winter mode (clockwise rotation). If they are moving counter-clockwise, it's set to summer mode (counter-clockwise rotation).
For summer use, the airflow should go down directly from the fan to the floor. For winter use it should pull the air from the floor towards the ceiling so it flows across the ceiling and around the room. So as to whether it should be clock-wise or counter clock-wise, that would depend on the angle of your blades. It's best to just stand under it when it's on. In the summer you should feel the air blowing on you from the fan and in the winter you shouldn't.
One way to determine if your ceiling fan is spinning clockwise or counterclockwise is to stand directly under the fan and observe the direction of the blades. If the blades are rotating in a clockwise direction, the fan is set to winter mode. If the blades are moving counterclockwise, it is set to summer mode. Additionally, you may feel a draft of air when standing directly under the fan that can help indicate its direction.
Fans should spin counterclockwise in the summer. The counterclockwise rotation pushes cool air down, while clockwise rotation can be used at a low speed in the winter to pull cool air up and push warmer air down.Keep in mind, though, that ceiling fans don't actually cool rooms—they just create a breeze that has a wind chill effect, making you feel cooler. So you can turn the fan off if nobody's home.
With a typical fan, run the fan counter-clockwise in the summer, and in the winter, run the fan clockwise at a low speed. In the summer, blow the air down to directly cool you. If you have a large room, and you are on the outside of the room, you may want to run the fan in the opposite direction. In the winter, blow the air up on slow to pull the cool air up, mixing the cool air with the warm air at the ceiling, and pushing the air across the ceiling to the walls, then coming down the walls, and minimizing wind chill.
In most cases, ceiling fans rotate clockwise in the winter and counterclockwise in the summer. Clockwise rotation in winter helps to push warm air down from the ceiling and circulate it throughout the room. Counterclockwise rotation in summer creates a breeze that can make the room feel cooler by promoting evaporation from the skin.
For most models your ceiling fan blades should be turning counter clockwise in the summer. As a general rule, the blades need to spin in the direction of the slope on the blades to create a downward draft which makes the air feel cooler. You should feel a draft or breeze when you are standing underneath the fan if it is turning in the right direction. If you do not feel that then you need to switch it to the other direction.
Ceiling fans typically run counterclockwise in the summer to create a breeze and help cool the room. In the winter, you can switch the direction of the fan to run clockwise at a low speed to circulate warm air trapped near the ceiling and help make the room feel warmer.
For rooms with high ceilings like 13-foot ceilings, the ceiling fans should be set to turn counterclockwise in the summer to create a breeze and promote better air circulation. In the winter, switch the ceiling fan direction to clockwise to help distribute heat more evenly throughout the room.