People start closing their pools in late August and some keep them open all the way until mid-October. Mostly it just based on personal preference, but here in Winnipeg, temperature is a huge factor. We tend to cool down a little bit by the beginning of September, people are going back to school, and this is the signal for the beginning of the end of pool season!
Other things that might influence individuals to close their pool a little earlier is whether or not they have a pool heater. A pool heater can extend the length of your summer significantly by up to 2 months. Having a lot of trees in your yard and around your pool might also influence you to close earlier to prevent dirt and debris from the fall season entering your pool. If you can not keep up with the leaves in your skimmer… then it is time to close the pool.
Before you get into closing your pool you should make sure that any problems are cleared up such as metals metals, or algae, and that your pool is balanced. The follow the winterization instructions with either BioGuard or Dazzle.
Hibernation with BioGuard. https://aqua-tech.ca/2019/08/are-you-guys-ready-to-hibernate-your-pools-bioguard/
Winterization with Dazzle. https://aqua-tech.ca/2019/08/winterization-for-your-pool-dazzle/