Turkey in October

The links will provide all the details for october balloon flights

https://turkeytravelplanner.com/special/balloon/index.html

https://slightnorth.com/cappadocia-hot-air-balloon/

We found the weather to be very mild and temperate in October, 2018. In the middle section in Cappadoccia, it was a little cooler because of the higher elevation but we had no rain to speak of. Istanbul was humid but mild. We were there Oct. 12 - 28. We went hot air ballooning in Cappadoccia. There are very strict about weather conditions for ballooning to ensure the safest ride possible.
We took the RS Best of Turkey tour and enjoyed it very much, quite an education! The friendliest people you will meet anywhere.

I did the balloon ride on October 31, part of the RS tour. Gorgeous. The tour was Oct 27 - Nov 7, weather was beautiful, not too hot, light jacket a few times, mostly in the crisp mornings.

The balloon rides depend more on wind conditions. I think it was iffy until a day before. If you are there on your own, you'll have more leeway, if the weather doesn't cooperate.

October is an ideal time to visit. I was there in October a few years ago, and the weather was fantastic for the most part. It was a bit drizzly on and off in Istanbul, but that could happen at any time of year. Everywhere else, it was sunny and the temperatures were moderate.

We had to delay our balloon flight by one day in Cappadocia. This sounds strange for a place as arid as Cappadocia, but I think there was a possibility of rain that never materialized.