The best time to visit My Son is February through August — the dry season in this part of central Vietnam. The site is exposed, with limited shade, and exploring it in heavy rain is unpleasant and can make paths slippery. October and November are the wettest months; typhoon season runs from September through December and can bring flooding to the entire Thu Bon river valley.
Within any given day, early morning is best. The tour groups from Hoi An typically arrive between 8:30 and 10:00 a.m. Getting there before 8:00 a.m. means relative quiet, cooler air, and dramatically different light — the low morning sun catches the brick textures and carved surfaces in a way that midday flat light completely misses. The site is open from 6:00 a.m., making an early start easily achievable.
Cham dance performances are staged at the site daily for tour groups — usually short, tourist-oriented shows in the main amphitheatre near the entrance. They are optional and add nothing to understanding the temples themselves, but the music and movement draw on a living performance tradition that has some genuine connection to the Cham cultural heritage on display in the ruins.