I prefer winter over summer. Chennai only gets mild winter. So, we cannot call it winter per se. I like the months November, December, January and February. December is the best. It starts getting warm in March. April and May are sweltering. Humidity is high as Chennai is on the coast. One will sweat even if you stand under the shade or even indoors. The temperature might slightly dip in the months of June, July, August if the South-west monsoon is active. September is usually dry and Chennai gets the late Indian summer. October might cool down if the north-east monsoon sets in. November- February are pleasant.