There's plenty of skepticism around the effectiveness of standing fans and their window-mounted equivalents – but if you pay attention to the positioning and set-up of your fan situation, you'll get a lot more mileage out of these machines.
Smarter living editor Alan Henry of the New York Times recommends placing a room fan in front of a bowl filled with ice. As the ice melts, the fan's breeze distributes the water vapor, giving you a nice waft of cool air.
Or, according to Lifehacker, positioning a window fan so it's facing outward will blow hot air out of your stifling room.
As the outdoor temperatures drop overnight, the displaced warm air will be replaced by cooler air. If you leave a second window open for a cross-breeze, this can increase the effectiveness of this method.