Living in this Western world, I often tell people that if they want me to be somewhere, or to participate in something, they need to make sure I put it in my calendar. In the fast pace world, that Monday to Friday marathon, followed by the short sprint of weekends on repeat means that we have to either be extremely organized or else we'll get lost.
But, if you ask me when Thunder dance happens, I can tell you with certainty that the people will come together in the spring time, after the snow has turned to rain, and the trees are budding and at the first crack of thunder heard in the distance. It could be on a Tuesday or a Saturday, but it always comes with the first rains after the long cold winter.
Indigenous ways of marking time are dictated by what is happening in the natural world, including the life cycles of the plants and animals and most importantly, the moon. Sometimes, the timing can be consolidated with the 12-month calendar and sometimes, it runs it's own course.
When I was a student teacher in the Cree community, the school board did not plan for a March break, but instead, mapped out floating weeks in the spring that would align with the goose hunt; they called it Goose Break. But when talking to the locals, they told me that if the geese came early, then they were going to meet them, regardless of the calendar. And that is a beautiful example of the ways in which some nations are still living in their traditional, uncolonized ways.
Below are two versions of a "Calendar" that you can use to explore time with your students; I've included some resources that can help you, even if you want to simply do your own learning as well.
Image borrowed from: https://earthtotables.org/essays/language-and-food/