Waawiita Kiilhswa ‘Lost Moon’ makes its appearance every three years. In the recent past, Waawiita Kiilhswa was inserted in 2013, 2015, and 2018. We do this because our lunar calendar is ecologically based and must connect to the ecological changes referenced in the calendar. A lunar year is approximately 11 days shorter than a solar year. Over time, our month names start to shift away from the ecological indicators that give them their names. In our community, we currently use pahsaahkaahkanka ‘the summer solstice’ as our indicator of when to insert Waawiita Kiilhswa. By adding Waawiita Kiilhswa every three years, we ensure that pahsaahkaahkanka falls within the proper lunar month: Paaphsaahka Niipinwiki ‘Mid-Summer.’ By following this pattern, we maintain a connection between our lunar calendar and our ecology. Typically, Waawiita Kiilhswa is inserted during the dead of winter, after Mahkwa Kiilhswa ‘Black Bear Moon’ when everything is quiet. As a result, Waawiita Kiilhswa does not have a set of ecological changes associated with it.