This article aims to explore and examine the customs of the Sasak people of West Nusa Tenggara in determining the season and ngandang rowot (beginning of the year) in rowot Sasak calendar system. This is a qualitative research with an ethnographic research design. The ethnographic design adopted from Spradley. The research instrument consisted of an observation guide and an interview guide. Data were collected through participatory observation, in-depth/unstructured interviews, photographs, video recordings, document studies, and artifacts.