The Summer-Winter feature allows the fan to rotate both anti-clockwise as well as clockwise. The former allows the fan to give you a cool breeze (for the warmer climate) while the latter gives you a cozy warm air effect (for the cooler climate).
Usually fans rotate anticlockwise to give you a breeze. There are times when it’s cold outside or you’re not feeling well, or in a couple – when one wants the fan and the other doesn’t – you may turn the rotation of the fan in the clockwise direction – which behaves as an exhaust and vacuums the air above, thereby giving you circulation rather than breeze. This is also handy over a dining table.