Weather is a condition of the air that surrounds the earth. Clouds, Wind, rain and snow are present in every kind of weather making it hot or cold, cloudy or clear, windy or calm. The earth has a variety of seasons and climates as a of weather. The weather affects out lives in numerous ways. The clothing we wear changes according to weather. When it is cold we wear heavy clothes and when it is hot we dress lightly. Those who live in Anuradhapura, Polonnaruwa, and Hambantota districts wear very light clothes as those places are hot throughout the year; those in Bandarawela and Nuwara-Eliya districts wear heavy clothes to keep themselves warm. Even the homes in those districts have to be heated during certain months of the year. Weather has an enormous impact on agriculture. It is during clear weather that farmers plant and harvest. The plants require sunlight and rain to grow and ripen. Floods and droughts damage and destroy the crops and the farmers have to bear heavy losses. Industry. Transport and communication suffer during bad weather. Continuous rain, floods and earth slips damage and wash away bridges, railways, roads and bring construction work to a stand still: Power and telephone lines are disrupted, villagers are completely cut off and isolated due to floods, Storms and earth slips. Fog and thunder storms disrupt air travel, radio and television broadcasts. The worst is disease and loss of lives due to bad weather. Weather and climate are not the same. Weather is a condition of the air during a brief period, whereas climate is the average temperature of region. Before the invention of scientific equipment to forecast weather, people adopted traditional methods. For example, color and the cloud formations visible to the eye; the movements cries and the behaviour of birds and animals; the changes in the air and temperature etc. But there was no accuracy in the forecast. Today weather is forecast using complex instruments, such as radar, satellite and computers. The forecasts are much more accurate than in the past.