I'm planning to be in Istanbul this weekend. I've been there before 2 times so I've seen already a lot. I've explored narrow steets of Sultanahmet, walked by feet from Taksim to Ortakoy, took the ferry to the seashore of Asian side and adored mimosa flowers there
But these days the weather is not expected to be good (cold and rainy)...So I don't know how to spend my time.
Anyway I still have plans to go to sea trip somewhere around. I remember I can go by public ferry to the Prince islands. Maybe somewhere else?
And do you have any advices what to to in Istanbul for 2 days of rainy weather?
Have you seen the Grand Bazaar (or Covered Bazaar)?
It is covered and huge...
If it is going to be rainy, I can recommend couple of museums to visit. Istanbul Modern, Garanti Sanat, Yapikredi Sanat, Rahmi Koc Museum, Sabanci Museum. I don't know their schedules but they all should have an English website.
Also check out this link for concerts and shows in Istanbul
Going to these museums could really be exciting. If you like technology and cars Rahmi koç museum could be a good choice. In Sabanci museum you can have a nice meal with a great view becides good exhibitions. Modern Art is also a very good choice. its very central. You can spend the rest of the day in Beyoglu. İstanbul archeology museum is another alternative.( I assume you have already see Topkapı and Dolmabahce).
If you don't want to go museums. You can spend your day in areas at Bosphorus like Tarabya, istinye, Emirgan (Sabancı museum is also at Emirgan).
Going to the islands is also a very good idea but be careful. If the weather is too windy, you have to spend the night at the island, so before going double check the forecast.