Please answer a question about the following article about Egypt:

Most of Egypt's rain falls in the winter months. South of Cairo, rainfall averages only around 2 to 5 mm (0.1 to 0.2 in) per year and at intervals of many years. On a very thin strip of the northern coast the rainfall can be as high as 410 mm (16.1 in), mostly between October and March. Snow falls on Sinai's mountains and some of the north coastal cities such as Damietta, Baltim, Sidi Barrany, etc. and rarely in Alexandria. A very small amount of snow fell on Cairo on 13 December 2013, the first time Cairo received snowfall in many decades. Frost is also known in mid-Sinai and mid-Egypt. Egypt is the driest and the sunniest country in the world, and most of its land surface is desert.

When was the last snow fall in Cairo?
13 December 2013,