Spending a day in Florence in the summer can get to you because it is hot and crowded. Getting away from the crowds is essential I think.
A great day trip from Florence includes Fiesole and the walled town of Monteriggioni.
Built in the 13th century , Monteriggioni is a walled town with a castle that was earlier used to guard from enemies.
There is a small piazza with a Romanesque church and a toursim office. Of course there is a Bar and a ristorante too. Ristorante Il Posso sits opposite the Bar and is adorable! I love its Tuscan exteriors and it is definitely worth sitting here for lunch. It has a great list of wine options and amazing Tuscan food (their steak is wow)!