UnhealthyEveryone may begin to experience health effects; members of sensitive groups may experience more serious health effects. Satisfactory May cause minor breathing discomfort to sensitive people.
The hottest time of the year is May and June (locals call this period 'Fire Star'), when temperatures climb higher than 40 °C / 104 °F. The coolest climate of the year arrives during the months of December and January, when daytime temperatures typically hover around 20 °C / 68 °F.
This is the busiest tourist season, especially among Western travelers who are drawn to the cultural and historical sites, rather than to the water parks south of Chennai. Of note, hotels charge some of their highest rates during this season. The south-west monsoon delivers rainy weather to Chennai from June to September, but the amount isn't that high during this period.
Much higher levels register during the north-east monsoon, which lasts from October to December and delivers more than 127 cm / 50 inches of rain.