Is the 12-month starts from 1st Jan to 31st Dec?
If so, stay from 1st Aug to following year 31st May still within 183-day rule in 12 months?
If you reside in Canada for 183 days or more in any 12 month period, then you will be deemed to be a tax resident of Canada. Residents of Canada, including deemed residents, are taxable in Canada on their worldwide income.
In your example, you plan on residing in Canada from August 1 to May 31 of the following year. Therefore, you will become a deemed resident of Canada, since you will have stayed in Canada for at least 183 days.