A ceiling fan should rotate counterclockwise in the summer so the blades push cooler air down in a column.
Attic fan blade orientation.
Whole house fans are used to blow hot air out of the attic by sucking cool air through the house up though the whole house fan and out though the gable vents in the attic.
This is the best ceiling fan direction for air conditioning since it makes the air feel cooler than it is.
It allows you to turn your thermostat up a few degrees.
The leading edge of the blade will be covered with dirt.
Likewise if the blade is angled down and the fan turns the opposite direction the reverse is true.
If a blade is angled down and the fan turns in the same direction as the blade angle it will blow forward.
Fan blade rotation is determined to be either clockwise or counterclockwise when viewed from the air discharged side.
These fans are usually wired to run in one direction.
The motor s nameplate depending on manufacturer may contain information on direction of blade rotation.