Wan Nao is traditionally devoted to preparation before Songkran’s New Year day.
Observed on April 14 in the classic three-day sequence, Wan Nao is associated with preparing food, offerings, and other items needed for religious and family observances. It falls between Wan Maha Songkran on April 13 and Wan Thaloeng Sok on April 15.
The day’s practical role helps explain why Songkran is more than a single water festival. Families may prepare meals, visit temples, make merit, and organize gifts or offerings for the next day’s ceremonies. Local customs can differ, so not every community follows the same timetable in exactly the same way.
Wan Nao is sometimes confused with the main water-splashing days seen in tourist centers. Its traditional emphasis is preparation and religious activity, although contemporary public celebrations may overlap across the whole holiday period.