For the Stó:lō, sílólem (the year) begins around mid-October. Each month is marked by one complete cycle of the moon (which takes approximately 29.5 days), so although there are usually twelve months per year, there are years when there are thirteen moon (a leap year). According to the “First Stalo Calendar 1976-77” (SRRMC, 000673), “…the Stalo people probably took the events described in the names of the months as more important than rigid mathematical periods.” Months are named after the moon of that month, with the moon’s name being a description of natural occurrences or activities that take place during that month. When there are thirteen moons, the name of the thirteenth month depends on when the moon appears, and as a result, some months have more than one name.

In the past, people typically kept track of days and months by tying knots in string made of stinging nettle twine or cedar bark (one small knot each day, and a larger knot for the month). Others kept track by spiking sticks into the ground.