Thrissur features a Tropical Monsoon climate (Köppen climate classification *Am*). Because of its proximity to the equator and the Arabian Sea, the city experiences hot, humid weather year-round, with relatively minor fluctuations in temperature.
The year is divided into three main seasons: summer, monsoon, and winter. Summer stretches from March to May, bringing high humidity and daytime temperatures that frequently peak around 35°C to 37°C (95°F to 98°F). The Southwest Monsoon arrives with dramatic force in early June, bringing torrential rainfall that lasts through September. A lighter, retreating Northeast Monsoon brings additional showers in October and November.
The most pleasant time to visit Thrissur is during the brief, mild winter from December to February, when temperatures average between 22°C and 30°C (71°F to 86°F) and the skies are generally clear. The world-famous Thrissur Pooram festival typically falls in April or May, a spectacular albeit sweltering time for visitors.