The short answer
Yes, especially in the first half. December brings bright days of about 19 °C, cold nights of about 7 °C, snow on the Atlas and good Sahara weather. The first two weeks are calm. From about 19 December the Christmas and New Year rush makes it the busiest fortnight of the year, so book early.
In more detail
Our climate table gives December a high of about 19 °C, a low of about 7 °C and some rainy days. Sunset is at about 17:33 to 17:39 through most of the month, so days are short and evenings cool quickly. A sunny riad courtyard at midday and a hammam in the late afternoon are the winter rhythm.
Early December is quiet for foreign visitors, though the Moroccan school break of 6 to 13 December 2026 brings domestic families to the Agafay and the mountains. From about 19 December demand from Europe peaks. New Year's Eve 2026 is a Thursday, and at least one Agafay camp closes New Year bookings on 15 December.
It is a good month for the desert if you dress for cold nights, and for the Atlas, with snow on the peaks. The Tizi n'Tichka can see snow, so leave slack in a Sahara plan. Christmas Day is an ordinary working day in Morocco: shops and souks open as normal.