I arrived on April Fools Day which is near the end of the dry season. Sometime in May it began to rain - for six months until November. A lot has changed there in the last half century. China, Thiland, Laos and Cambodia have built dams and it was a dry winter in Tibet and Burma. The Mekong is lower than it has been in over a century. For anybody interested in geography, this is interesting stuff.
https://www.lowyinstitute.org/the-interpreter/bad-dry-season-mekong