and i assure you, you wudnt regret it. i went there for my honeymoon. everything aside, the weather is just gorgeous.. i loved it to death. the places are nice.. go to blue mosque and grand bazaar... must c. ure goin in dec, itll b quite chilly. i went in Nov last year and had to wear 2 shirts and a coat on top but i lovvvvvvvvvvvvvved it.... enjoy!
Yeah, I checked their average temperatures in Dec and found out that it will be a little chilly but it's fine coz we are used to a lot more colder weather. But I read in dec it is very rainy in Istanbul and the best time to go there is April.