- Laos has the typical tropical monsoon climate of the region, though the mountains provide some variations in temperature. In October, rains start to taper off, and the cool season begins in November, lasting through February. 

- In March "mango rains" occur. March, April, and May are hot and humid.  The winds of the southwest monsoon deposit an average rainfall of between 50 and 90 inches (1,300 and 2,300 millimetres), with totals reaching 160 inches on the Bolovens Plateau.

- In April, the hottest month, temperatures in Vientiane range from 22°C to 34°C, and in January, the coolest month, 11°C to 28°C. Temperature extremes of 40°C (April) and 4°C (January) have been recorded.

- The dry season (November to April) is dominated by the northeast monsoon. Minimum temperatures average between 16° and 21° C in the cool months of December through February, increasing to highs of more than 32° C in March and April, just before the start of the rains. In the wet season the average temperature is 27°C.