Weather in Istanbul:
The weather in Istanbul very hot and humid in summer In winter it will be freezing, the best time to travel there in May and September the weather will be great there.
For tours:
There are many lovable tours you can do it in Istanbul:
Walking Tours : walking and watching beautiful gallery too for artists ,really very amusing tour.
Istanbul Bike tours : It will be a fun and amazing tour when visiting most popular attraction on the bike.