The Papagayo is caused by a surge of cooler, drier air originating from the North American continent. Such surges are more common in the winter, but may occur at other times of the year as well. This air is denser than the tropical air mass normally present in the region, thus a strong pressure gradient is established which induces the wind. The wind is further accelerated by the funneling effect of the mountain gap between the Caribbean and the Pacific coastlines. The same conditions are the cause of the Tehuano wind in southern Mexico and the Panama wind to the south.