As one of the districts in Tamil Nadu, India, Thiruvannamalai experiences a tropical climate with a major part of its annual precipitation occurring during the monsoon season. The district comprises of five taluks namely Thiruvannamalai, Polur, Chengam, Vedanthangal, and Kilpennathur. The average rainfall received by the district is around 890 mm, which is considerably higher than some other districts in Tamil Nadu.
The rainy season in Thiruvannamalai starts in June and lasts until November, with August and September being the wettest months. On average, the district receives around 40% of its annual rainfall during the southwest monsoon season (June-September) and the remaining 60% from the northeast monsoon season (October-November). The northeast monsoon season is the most crucial for the district, as it accounts for more than half of its annual rainfall.
The district experiences two types of rainfall – convectional and cyclonic. Convectional rainfall occurs due to the uneven heating of the land, leading to the formation of clouds that later precipitates. Cyclonic rainfall occurs when the district comes under a low-pressure area, leading to the ascent of moist air and formation of clouds that precipitate.
Despite the average rainfall being satisfactory, Thiruvannamalai often faces rainfall deficits, which has been a point of concern for the district’s farmers. In recent years, the district has experienced frequent droughts, which has led to the unsuccessful growth of crops and subsequently affected the livelihoods of the farmers.
In conclusion, Thiruvannamalai district receives a significant amount of rainfall, and the majority of it is from the northeast monsoon season. However, the district frequently experiences rainfall deficits, leading to droughts and affecting the agricultural community. Proper measures need to be taken to mitigate the adverse effects of the rainfall variability and protect the rural livelihoods in the district.