You will be prevented from going on deck if there are strong winds on deck, otherwise there is no restriction. The are numerous bars which open and close at different times depending on location. The ships information will give you details.
There are no restrictions on when you may go on deck, perhaps in very bad weather but you don't want that on your holidays. There are various bar on the ship they all operate different hours but your daily programme you get when you are on board will advise this. There will be set our for the bank and also for the casino which can only be open when the ship is at see and if in port it will likely open about 30 mins after you leave port as will the duty free shops. If you did have an overnight stay in a port this means these two will not be o.pen. Hope you find this helpful.
You will be free to go on deck at any time that you wish providing your safty is not put at risk. The bars tend to shut when they run out of customers! They will stay open until 2 O'Clock in the morning if you want to stand there buying drinks! Happy cruising.