Istanbul weather is volatile, more than anything; you can get all four seasons in one day. That's because it sits between the Black Sea and Aegean weather systems, and in a wider sense between the Mediterranean and Eurasian Continental ones.
April is particularly unpredictable, it could be sunshine and very pleasant almost summery temperatures (20-25C), or it could be horizontal rain and miserably cold (10C), or anything in between.
Also, given that April is sort of transitional month between spring and summer, it makes a difference whether you're talking about early or late April. March is still very much wintery early spring, whereas May is looking distinctly more like summer, and April sits somewhere between the two.
Usually between 18-21 C with some rain.
You may find 2014 April weather below
http://www.accuweather.com/en/tr/istanbu...
April is the month that it starts to get warmer. It might be a little cold at the beginning of April, but generally it's just like a spring weather.
No, it's 20+ degrees there in April, it's very warm part of the world
Too cld for what? Keep you clothes on, you'll be fine. Don't do anything like that in public in Istanbul, you'll get arrested.
