Grand Princess: Med. Cruise, How many formal nights and when?

[mik]

Could someone tell me how many formal nights there are on the 12 night med. cruise on the Grand Princess? When are they? Does this change much from voyage to voyage? I know this cruise is port intensive and that there will be a lot of walking, touring, etc. How busy are formal nights. Do people tend to skip some of the formal nights because of the late returns to the ship or are they scheduled on sea days. Thanks for your help.

[ucalegend]

There are two nights. They are both on the days at sea.