The word "monsoon" comes from the Arabic word "mausin," which means season. Even though a lot of people think that monsoons mean a lot of rain, monsoons really are a seasonal shift in wind direction. Because it is based on wind, a monsoon can be either WET or DRY.

Monsoons, or the changes in wind direction, are caused by the fact that land heats up and cools down faster than water. During the day, when the sun is beating down strongly, the air above the land is warm, so it rises. The cooler air from the water moves in to replace it. This creates a wind gust. A similar thing happens during the night. The land is cooler than the water, so it creates a wind from land to water. (check out the figure on the left)

This kind of storm usually affects countries that are near or surrounded by large bodies of water. Some examples of such countries are India and Indonesia. Here, these "land-sea breezes" can cause major changes in the flow of the ocean and wind currents in that part of the world. Monsoons do occur in the United States, as well. The southwestern US receives rain from the wind that pushes upwards from the Pacific Ocean.

Monsoons usually affect the countries of the Indian Ocean. During the summer monsoons, wind moves from southwest to northeast (from the ocean to the land). When this happens, the winds bring a LOT of rain. This rain can sometimes cause flooding, damage, and deaths. However, the rain is helpful too because a lot of farmers depend on it to water their crops.

The winter monsoons are usually hot and dry. The winds move from northeast to south west (or from land to the ocean). There is little rain and temperatures can go up to 110 degrees F.

Check out the maps on the left that show you wind directions during the different monsoon seasons!