Can I deduct a rental loss if my personal-use cottage is only rented out part of the year?

It's possible, but a cottage used personally for part of the year and rented out for the rest raises its own complications. Expenses have to be prorated between the personal-use period and the income-earning rental period - you generally can't deduct the full year's expenses against rental income that was only earned for part of the year, so the math itself is more involved than for a property rented out full-time.

Beyond the apportionment issue, if the personal-use portion of the year is significant relative to the rental period, CRA may also question whether the rental use genuinely has a profit motive at all, which ties into the broader restricted-loss and reasonable-expectation-of-profit concerns covered in related questions. A cottage rented out for only a small part of the year while being used personally the rest of the time is more likely to draw this kind of scrutiny than one rented for most of the year with only occasional personal use. Keeping a clear log of exactly which days were rental use versus personal use, and pricing the rental period at a genuine market rate, is the most useful evidence for supporting both the expense apportionment and the profit-motive question.