Bihar is mildly cold in the winter, with the lowest temperatures being in the range from 4â€“10 Â°C (39â€“50 Â°F). Winter months are December and January. It is hot in the summer, with average highs around 35â€“40 Â°C (95â€“104 Â°F). April to mid June are the hottest months. The monsoon months of June, July, August, and September see good rainfall. October, November, February, and March have a pleasant climate.