A: The climate of Thailand varies widely from region to region. Rainfall patterns and temperature levels are subject to the monsoon. The summer monsoon brings three distinct seasons: cool (November-February), hot (March-June), and rainy (July-November). Monsoons, not latitude, determine the seasons in Thailand. Monsoons are seasonal winds that change direction during the year as a result of differences in temperature and pressure between land and sea. Derived from the Arabic word mansim, monsoons are the life source for farms across the country.