Who says you can't sail in summer in Florence?
The photo & article below are from my favourite Florentine publication,
The Florentine

Following the example of Paris, London, Rome and Berlin, Florence opened its first beach and bathing area along the banks of the Arno. Located just under the San Niccolò ramp, near Piazza Poggi, the so-called Lungarno Beach is equipped with sand, walking paths, complementary lounge chairs and umbrellas, a volleyball court, a bar, showers and three large cabanas to provide shade in hotter-than-normal temperatures. Because the Arno River is not fit for bathing, the cabanas feature vaporizers to give fast heat relief. What better place to kick back and relax at your lunch break or for the afternoon than here-immersed in the architectural and artistic jewels of Renaissance Florence, deep in the heart of the city.

Lungarno beach, open from 10am to 10pm until September 14. Includes a fenced playground for children, and a walking path leading to Ponte alle Grazie. Free entrance.