Luang Prabang weather: best time to travel
But this is also the season when tourist numbers are highest. Go in the rainy season (April-July and Sept-Oct), when 'rain' means a brief cleansing shower most afternoons, but otherwise lovely weather.
If you visit in October, you shouldn't miss the Bun Awk Phansa boat races held on the Nam Khan and Mekong rivers.
Avoid March when temperatures are searing. The Lao New Year festivities (from 13 to 15 April) are a worthy draw, and the tradition of throwing water is delightful and tonic.