Assam has 2 distinctive climates. The hilly areas enjoy sub-alpine climate while the plains of the state experience tropical climate with high humidity in the monsoons. Winter approaches here in the end of October and lasts until the end of February. During this time the nights are cold and the mornings are foggy. Summer begins by mid-May with high level of humidity and rainfall. June is the beginning of monsoon. Thunderstorms are a frequent occurrence during the afternoons. The best seasons of Assam are the spring and autumn with moderate temperatures and light rainfall.