On the Teesta, this district's monsoon is heavier and longer than southern Bengal's — heavy rain on the Bhutan hillslopes frequently floods the Teesta between June and September. Winter temperatures do not fall far, but dawn fog lingers long over the tea gardens.
Usually June–September, when heavy rain falls on the Bhutan–Sikkim hills. Riverside areas should stay alert whenever heavy rain is forecast.
January nights stay between 9–11°C — slightly colder and foggier than southern Bengal, but nothing like the hills.
October–March — less rain, controlled humidity, the most comfortable window for safaris and travel.