Please be aware that Istanbul has multiple airports and that these results are for all airports serving the city.
The best month to fly between Istanbul and Jeddah is September and the most expensive month to fly is August. (Average prices, based on 531 datapoints.)
The cheapest airline flying from Istanbul to Jeddah is Nas Air. They are 36% cheaper than Turkish Airlines. (Average prices, based on 538 datapoints.)
The best time to fly is at around 22. (Average prices, based on 635 datapoints.)