What is the weather like at Wutaishan in the second week of July?

Well, the temperature during that period of time is 50 F to 68F.
It's cool and comfortable. Beside T-shirts and jeans, you are suggested to bring a light jacket in order to adapt large temperature difference.
The transportation inside the scenic area is convenient. There are several sightseeing buses that can take you to those temples directly. Don't worry.
Have a good trip!