Cisco beach is situated in the south-west of Nantucket island, which is at around 30 mi / 48 km in the south of Cape Cod.
This beach is known as a very good surf spot for all types of surfers, amateurs and experienced ones. Usually the wind comes from the south-east and south-west. The beach has a sandy bottom, but one should be careful of several rips.
Best swell is from the above mentioned directions, meaning south-east and south-west. Cisco beach has two break points, left and right and on a normal day the waves length is around 50 to 150 m/164 to 492 ft, although on a good day you can see waves of 150 to 300 m/492 to 984 ft.
Best season to visit Nantucket island and Cisco beach is from May to September. In September though, there are less tourists so more space for performing your favorite water sport.
As Nantucket island welcomes many tourists in the summer, the prices are a bit high when it comes to accommodation and dining, but if you do a good search, you can certainly find several less expensive hotels and restaurants.