Sri Lanka’s agricultural industry depends heavily upon the weather changes brought by the seasonal monsoons.
Although only nearly ten percent of Sri Lanka’s GDP is made up of agriculture profits, seventy to eighty percent of the population is rural and depends on farming for their food supply. Because such a large fraction of the population relies on crops to feed themselves, variations in the weather cycle can have far-ranging consequences.
The most well-known aspect of weather in vicinity of the Indian Ocean is the monsoon. While the term monsoon is often casually assumed to refer to a rainy season, a monsoon is actually defined as a seasonal change in the direction of the prevailing winds of a region, the accompanying changes in precipitation being only incidental. The actual word “monsoon” is believed to be derived from the Arabic word for “season,” mawsim.
Because of this, South Asia actually has two monsoon seasons annually, incorporating both rainy and dry weather. In Sri Lanka, these are known as the Yala (southwest) monsoon and the Maha (northeast) monsoon, the Yala monsoon coming in the summer season and the Maha monsoon coming in the winter months. The Yala generally lasts from about May to September, and the Maha from November to February, with the periods between being designated as the inter-monsoons. Because monsoon actually refers to the prevailing winds, the heaviest rains do not normally fall on the island during the monsoons, but actually fall during the second inter-monsoon.
Due to the directionality of the winds, the areas of the island that are affected by each particular monsoon also vary. The Yala brings more rain to the south and west coasts, while the Maha brings rain to the north and east coasts. However, the inter-monsoon rains can happen anywhere across the island. As such, planting season is often coordinated with the monsoon seasons, lining up the harvest so that it will coincide with the dry weather after the rains. Also, to compensate for the smaller rains of the Maha, farmers in the north and east must often rely on irrigation tanks during the Yala to water their crops.
North America also has areas that undergo monsoonal changes. The North American Monsoon lasts from about June to September, traveling through Mexico and the American Southwest. While the wet season in Florida is sometimes exaggeratedly labeled as a “monsoon,” since a monsoon depends on prevailing winds and not precipitation, Florida does not have monsoonal seasons, simply a wet and dry season.