How many days are sufficient for a visit to Casablanca and which is the best month for visit?
One day would be enough, It is not exactly a tourist destination. Any time is good to visit, try to avoid public holidays.
Yes, one day or two are enough
I always think you need at least 7 days at a resort to get a feel of it. At the end of a week you will have had a taste of the place. I know agadir and marrakech but Casablancarians have told me Casablanca is good and few tourists. Bon voyage Tassa dude
1 or 2 days is enough for Casablanca - it depends what you like, there are beaches you can spend time, coffee beside the sea etc, the Hassan mosque is a must see and takes a couple of hours.
there are the Mauresque and provincial architecture buildings around the centre, the huge Africa mall with its big aquarium that you can take a glass elevator up through, a small old medina, the shopping souks such as the Habbous quarter.
If you really want to stay longer you can visit the Marjane supermarket... you can do day trips out of town to nearby beaches such as Mohammedia. a bit further away is Azzemour or just take a bus or train to Marrakech or north to Rabat and Sale.