Istanbul Weather in mid-Oct?

We are heading to Istanbul the third week of October ( or maybe not depending on the weather!) and I wanted to see who else has been there during this time and what your experience has been with weather. Reference guides and ave temps reported online only do so much, I want to hear from people that have actually been. I'm from the San Francisco Bay Area, if that helps as a reference to what I'm used to. I'm hoping for something not too cold. Should I expect rains or require a jacket during the day?

If I recall correctly, winters in Istanbul can be miserable affairs, though the really bad part doesn't hit until nov-dec.

Still, you will find it cold and wet, though usually not winter jacket territory.

Bring a waterproof jacket that insulates against a cold wind. Wear a sweater, or two, under it.

There can be a week of glorious 70's weather, or 60' weather, then it will plunge to 50 to 40 and miserable, so roll the die and find .

Its a great place to go no matter the weather. The ferry boats have indoor sections, and the doors are closed on the buses, so really, bring a waterproof, windproof jacket, LIGHT winter if possible(50 to 25 fahrenheit), and enjoy.

The hardest part would be having some of everything. It is that fun time of year where it could be a cold morning that gets real warm, then rains at night. Gotta love it though.