Of all the different climates found in the world the monsoon climate has the most defined characteristics. The word monsoon derives from an Arabic word for "season." It is broadly applied to all wind systems that seasonally reverse their prevailing winds on a continent. The best examples of these opposite direction wind flow patterns are found in Southeast Asia, from the Arabian Sea to China, the Gulf Coast of the United States parts of Africa, and northern Australia. More than anywhere else the subcontinent of India is greatly impacted by the monsoon. With few exceptions the people of the monsoon regions have become conditioned to rhythmic rainy summers and dry winters. Though both kinds of weather are predicted, it is the arrival time, duration of stay, and the extent of the rainfall or drought that is uncertain. That is why the monsoon can be so whimsical, and that behavior can prove to be a matter of life or death for monsoon region inhabitants where famine is hardly unknown. More than half of the world's people live in monsoon Asia, many of them in extreme poverty.
The decisive difference between the two seasons is based on a fundamental meteorological fact. Land heats and cools more quickly than water. Cooler heavier air tends to displace the warmer lighter air and push it skyward. Therefore, the monsoon effect brings denser moisture- laden air from the sea in summer (wet monsoon) and conversely causes the dry air over the land to flow seaward during the winter months (dry monsoon). In a way the monsoon's disposition is like a person who displays periodic mood swings or a double personality. Almost 80 percent of India's rainfall comes during one season alone, the summer months from mid-June though September, and has a tremendous impact on the lives of the people, especially those trying to survive in rural villages. Where the brutal summer heat and drought patches the earth amid stifling dust storms, people are encouraged to wear protective face masks in order to filter out lung-clogging dust particles.