Like the rest of Laos, Vientiane has a tropical monsoon climate, with mostly hot and humid weather year-round.
The peak tourist season is from December to February. The rainy season is over, and the heat relents. Daytime temps range from 64 to 82 degrees—still pretty warm and extremely pleasant. Another mini high season occurs in August. Accommodations can fill far in advance, so be sure to reserve rooms ahead of time.
The rainy season goes from May through October. Temperatures during this time are still fairly hot—averages between the high 70s and high 80s are common—so it can be pretty sweaty. Still, between the bursts of rain, it also can turn sunny and pleasant.
After winter’s high season, the heat picks up in March, though temperatures tend to peak in April, the warmest month of the year, when averages sway between 77 and 93 degrees.