My winter boutique hotel in Porto with a heated pool, Canto de Luz, is the only Maison in Porto’s old town with an outdoor pool heated and open every day of the year, from 09:30 to 19:30. Porto in winter is quieter, the restaurants are easier to book, the Douro valley is at its most cinematic, and the old town walks better in low season than it does in August. The Maison was lovingly restored so that off-season weeks feel like the right weeks, not the leftover ones.