is istanbul worth exploring during a winter stopover?

While the best season for Istanbul is from April to June and September to November, a winter stopover can still be rewarding. January averages around 7.1°C, which is colder than the peak months, but major historic sites like the Sultan Ahmed Mosque, Topkapi Palace, Süleymaniye Mosque, and Galata Tower remain accessible. If your flight arrives at IST and you have enough time, stepping out to see these sights or take in views across the Golden Horn is certainly worthwhile even during the off-peak season.