Winter is real, and summer wildfires can change plans

From December to March, temperatures in Montreal, Ottawa, and the Prairies routinely fall to −20 °C, and Toronto isn't much warmer; pack for it or stick to Vancouver. In summer, wildfire smoke can close parks and affect air quality in the West, sometimes for weeks; check the provincial wildfire and air-quality sites before a trip to the Rockies or the interior of British Columbia. Mosquitoes and blackflies in June and July are no joke in the north; bring repellent.