Laos Weather

The annual monsoon cycles that affect all of mainland Southeast Asia produce a 'dry and wet monsoon climate' with three basic seasons for most of Laos. The southwest monsoon arrives in Laos between May and July and lasts into November.

The monsoon is followed by a dry period (November-May), beginning with lower relative temperatures and cool breezes created by Asia's northeast monsoon (which bypasses most of Laos), lasting until mid-February. Exceptions to this general pattern include Xieng Khuang, Hua Phan and Phongsali Provinces, which may receive rainfall coming from Vietnam and China during the months of April and May.

Rainfall varies substantially according to latitude and altitude; the highlands of Vientiane, Bolikhamsai, Khammuan and eastern Champasak Provinces are wettest.

Temperatures also vary according to altitude. In the humid, low-lying Mekong River valley, temperatures range from 15°C (59°F) to 38°C (100.4°F), while in the mountains of Xieng Khuang the temperature can drop to 0°C (32°F) at night.