The Southwest Monsoon in Sri Lanka: A Vital Climate Phenomenon-by Kalani-eLanka The Southwest Monsoon, known locally as the “Yala” season, is a significant climatic event in Sri Lanka, influencing the weather, agriculture, and daily life across the island. Typically active from May to September, the Southwest Monsoon brings substantial rainfall, particularly to the southwestern and central regions of the country. This seasonal wind pattern is driven by the complex interplay of atmospheric pressures, ocean temperatures, and geographical features. The Southwest Monsoon originates from the Indian Ocean, where the intense summer heat causes air over the land to rise, creating a low-pressure area. Meanwhile, the high-pressure area over the cooler ocean drives moist air from the southwest towards the land. As this moisture-laden air encounters the island’s topography, particularly the central highlands, it cools and condenses, resulting in heavy rainfall. Sri Lanka’s diverse topography plays a crucial role in determining the ...