What are the high temperatures (Fahrenheit in Greece in July? We are not looking for a beach vacation. Is it to hot to tour?

We were in Athens in late May 2022, and temps were in the 90’s. After touring the Acropolis, we had to find shade and bought lemonade to drink. Be sure to have water with you, hats, and sunscreen.

Visit the Acropolis in the morning. Visit museums in the afternoon. And also visit the Athens Central Market when it’s hot. It’s cool and very interesting.

You can find temperatures from previous years by googling something like historical weather Athens. I've been there in August and it was really hot. Too hot to do very much other than seek shade and a cold drink. We still enjoyed the trip but would not go back in summer.

Count with around 95 F, certainly not more than 100 F(in early afternoon).
All museums and indoor things are airconditioned.
So are metro trains, trams and buses.
The Cycladic Islands feel cooler, because there is always a strong wind from around 10am until 5pm

If you want to visit cites (Athens, Thessaloniki), in my opinion the best period to visit Greece is April - May.