The geographical location of Tamil Nadu is such that the climatic condition shows only slight seasonal variations. Due to close proximity to the Sea, the temperatures and humidity remain relatively high all the year round. The climate of Tamil Nadu is tropical in nature with little variation in summer and winter temperatures. While April-June is the hottest summer period (with the temperature rising up to the 40ºC mark), November-February is the coolest winter period (with temperatures hovering around 20ºC), making the climate quite pleasant.
It is interesting to note that Tamil Nadu gets most of its rains from
the North-east Monsoons between October and December while the state
remains largely dry during the South West Monsoon season. The average
annual rainfall in Tamil Nadu ranges between 25 and 75 inches a year.
During summers (April to June), the coastal areas of Tamil Nadu become
awkwardly warm and humid, but the nights become cool and pleasant due to
sea breeze in the afternoon. During the hot season, the charming hill
stations of Tamil Nadu provide much needed respite from heat and
humidity. The period between October to March (when the climate becomes
pleasantly cool) is the ideal time to visit Tamil Nadu.