Weather in Tamil Nadu
Tamil Nadu is home to 58 cities tracked on Mausam Online, including Chennai, Madurai and Tirunelveli. Live weather, hourly forecasts and air-quality data are available for every city.
Climate & seasons
Unlike most of India, the greater part of Tamil Nadu gets more of its rain from the northeast monsoon, from October to December, than from the southwest monsoon of June to September, much of which the Western Ghats block. In Salem, Vellore and Hosur, though, June to September brings more rain than October to December. Rain is usually heaviest in October and November, when cyclones from the Bay of Bengal can also strike the coast. The heat peaks from March to June, before the rains.
When to visit Tamil Nadu
The most comfortable months to visit are January and February: the northeast monsoon is over and the heat has not yet built. Heavy rain is likely in October and November.
Air quality in Tamil Nadu
Each city's page, linked above, tracks PM2.5 and PM10. Tamil Nadu cities follow the broader South Asian pattern — cleaner air in the monsoon, more pollution in winter.