The factors regulating the climate of Bihar are:
The climate of Bihar is represented by the following seasons :
The onset of the rainy season takes place when a storm from the Bay of Bengal passes through Bihar. However the monsoon may set in as early as the last week of May or as late as the first or second week of July. The winter days are warm and mild but after sunset, the temperature drops abruptly, creating a sense of sharp coldness. Average temperatures in November in Bihar range between 19.6°C to 22.2°C. with January usually the coldest month. The average minimum temperature is between 7.5°C to 10.5°C though temperatures in Netarhat even fall to 7.5°C.
Similar to most of northern India, Bihar witnesses thunder-storms and dusty winds in summer. The hot winds (loo) of Bihar plains blow in April and May averaging a speed of 8-16 kilometers per hour. The rainy season begins in June. The rainiest months are July and August. In three particular zones, rainfall surpasses 1800 mm. The south-west monsoon normally retreats in early October and is accompanied by tropical cyclones arising in the Bay of Bengal and typhoons from the south China sea.
The climate of Bihar is characteristic of that experienced by most of northern India.
