The best time to visit Laos depends on your priorities. The dry season from November to April has almost no rain and temperatures are more moderate. The wet season from May to October is marked by tropical downpours in the afternoon.
The tropical capital of Laos is marked by typical wet and dry seasons. The best time to visit is from November to March, which is drier and slightly cooler, with lows around 17°C and highs not quite reaching 30°C until it starts to heat up in March. Almost no rain appears at this time of year so tourist numbers reach their peak. April and May are hot with highs around 34°C and temperatures peak at around 31°C between June and October, with lows around 24°C . Heavy afternoon rains occur from May to September, however this rarely affects travel.
Temperatures in Luang Prabang are similar to Vientiane, with evenings a few degrees cooler. The heaviest rains occur from June to August, reaching nearly 300mm (12 inches) with some rainy afternoons a couple of months either side. November through to March is the best time to go with temperatures averaging 27°C (83°F), although some people prefer to go during wet season when there are fewer travellers and the countryside bursts with colour and earthy scents after brief downpours.
Vang Vieng is known for its beautiful limestone and its adventure activity capital of Laos, where travellers go caving, rock-climbing, rafting and kayaking. During the wet season from May to September the Nam Song River fills up and flows up to four times faster. While this does not stop activities, extra caution must be taken. This also applies to caving and rock-climbing as heavy rain can cause pathways to become slippery and dangerous. This is the best time to visit to see the lush green mountains glistening after heavy afternoon rains and the spectacular scenery when it is at its finest.
In the south of Laos, from June to September, it is very heavy rains with over 300mm (12 inches) each month. This can prohibit travel by unsealed road, however this is the best time to travel by boat, a common way to get around southern Laos. From November to March, the weather is drier and cooler, the best time to travel by land, while March through May is known as the hot season with 34°C of temperature and evenings rarely drop below 25°C.