Laos has a tropical monsoon climate. In the months March to May, when the southwest monsoon brings humid air masses, the temperature usually rises to about 42°C (e.g. in Vientiane). During the months of May to October there is heavy rainfall (monsoon). Not only during this time the humidity is high (72 to 86 percent). The months from the end of October to February are cooler and drier. They correspond approximately to southern European autumn.
The best time to travel is between November and March.