Morocco has subtropical climate, depending on winds of the Atlantic ocean. It is very similar to Mediterranian. But temperatures and precipitation depend on region and altitude. Winter lasts from November to February or mid-March, it is the coldest and the wettest time of the year.
Along the Atlantic coast, in the north, places like Rabat and Casablanka, enjoy a very mild and pleasant winter with some rainfall. The northern part of Morocco gets much more rain than the dry south, especially on the coast. The rainiest month is November.
Inland areas get much colder than the coast. In the Sahara Desert, it's close to freezing during nights. The Atlas Mountains are cool and have enough snow for skiing and snowboarding since December. Marrakesh has a semi-arid climate, which means winter there are chilly, but still far from freezing.