Bucoleon by Cheers

The best time to visit Istanbul is from late April to June and September to October, when temperatures are mild and rain is less frequent. July and August are the hottest and driest months, with highs around 30°C, while December and January are the rainiest, with over 12 rain days per month. Spring and autumn offer comfortable sightseeing weather, though May can still see some showers. The city is pleasant in early summer before the peak heat arrives.

Stay in Sultanahmet for the main sights: Hagia Sophia, Blue Mosque, Topkapi Palace, and the Basilica Cistern are all walkable. It suits first-time visitors. Sisli is a modern, central district with shopping and business life, good for those who prefer contemporary comforts. For a quieter, upscale coastal stay, consider the Bosphorus area around Tarabya. Hotels like the Radisson Hotel Istanbul Sultanahmet and GLK Premier Acropol Suites & Spa are in Sultanahmet, while the Hilton Istanbul Bomonti and Fairmont Quasar are in Sisli.

Start with Hagia Sophia Grand Mosque and the Blue Mosque, side by side in Sultanahmet, for their unmatched history and architecture. Topkapi Palace Museum is next, the Ottoman sultans' residence with courtyards and relics. The Basilica Cistern is a cool, atmospheric underground marvel. Then head to the Grand Bazaar and Egyptian Bazaar for their vast, historic market halls. End at Galata Tower for panoramic views over the old city and the Bosphorus.

The full-day tours from Istanbul go to Gallipoli, a historic peninsula known for its World War I battlefields and memorials. The other tour covers the Old City sights within Istanbul itself, so for a day trip beyond the city, Gallipoli is the main option. You could also consider a ferry across the Bosphorus to the Princes' Islands, a car-free spot with pine woods and old wooden houses, or a short trip to the Asian side's Kadıköy for its waterfront and market streets.

Plan 4 to 5 days. In 3 days you can cover the Old City highlights: Hagia Sophia, the Blue Mosque, Topkapi Palace, Basilica Cistern, and the Grand Bazaar. Add a fourth day for Galata Tower, Dolmabahçe Palace, and the Egyptian Bazaar. If you take the Gallipoli day trip, add one more day.