Ordinarily, this only happened within the eve of the complete moon. So the most beneficial time to go to Hoi An was in the full moon. With the event of tourism in Hoi An, this now occurs on the nightly basis, so everyday is the greatest time to go to! https://h-i-in-n94688.pointblog.net/the-definitive-guide-to-hoi-in-an-89054095