Arunapuram experiences a tropical monsoon climate (Köppen climate classification: *Am*). The weather is generally warm and humid throughout the year, with temperatures typically ranging from 22°C to 34°C (71°F to 93°F).
The area receives abundant rainfall, averaging over 2,500 mm annually. The Southwest Monsoon (Edavappathy) brings heavy downpours from June to August, while the Northeast Monsoon (Thulavarsham) provides additional rainfall with frequent thunderstorms in October and November. The dry season runs from December to May, with March and April being the hottest months. The best time to visit is from September to February, when the weather is relatively cooler and the landscape is lush and rejuvenated by the monsoons.