If you are new to Chennai and stayed for a year round period you will not feel the winter as all the time in Chennai is hot and humid.
The maximum temperature you feel is in may and june of the year which will fall in between 38 degree Celsius and 45 degree Celsius. And coolest is on December and January when the weather is 19 degree to 22 degree Celsius. Due to less Rainfalls in Chennai, water scarcity is more.