Monsoon
The word "monsoon" is derived from the Arabic word "mausim," which means "season." Fittingly, it refers to the seasonal winds created each year during the summer season, when the Earth is tilted toward the sun. This causes land masses to become hotter. The heat from the land warms the air directly above it, causing the air to rise. Cooler air from the ocean rushes inland to fill the void left by the rising hot air, carrying moisture which condenses into heavy rains. This is a typical or "wet" monsoon.
Dry Monsoon
The dry monsoon occurs during the winter season when the Earth is tilted away from the sun. At this time, the ocean receives most of the sun's heat, warming the air above it. The heated air rises. Cooler air rushes in from land to fill the void left by the rising heated air, but does not carry any moisture with it. People living in the lands from which the cool air originates thus experience a "dry" monsoon, where there are strong winds but no rain.
Recent Effects of a Dry Monsoon
In 2009, India experienced an unusually dry monsoon season. It had a deep impact on the economy, which is largely based on agriculture. Up to 70 percent of the population depends on income from farming. There was so little rain that several areas of the country experienced drought. Many crops and livestock died, resulting in a food scarcity, which increased prices by 30 to 40 percent, according to PRI's The World.
Locations
Wet monsoons occur mainly in India and Southeast Asia, though this phenomenon has also been witnessed in other regions of the world like North and South America, where it is not as strong. The dry monsoon of winter often replaces the wet monsoon of the summer season in India.