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. Frost is also known in mid-Sinai and mid-Egypt.
Temperatures average between 80 °F (27 °C) and 90 °F (32 °C) in summer, and up to 109 °F (43 °C) on the Red Sea coast. Winter temperatures average between 55 °F (13 °C) and 70 °F (21 °C). A steady wind from the northwest helps lower temperatures near the Mediterranean coast. The Khamaseen is a wind that blows from the south in spring, bringing sand and dust, and sometimes raises the temperature in the desert to more than 100 °F (38 °C).
Prior to the construction of the Aswan Dam, the Nile flooded annually (colloquially The Gift of the Nile) replenishing Egypt's soil. This gave the country consistent harvest throughout the years.
The potential rise in sea levels due to global warming could threaten Egypt's densely populated coastal strip and have grave consequences for the country's economy, agriculture and industry. Combined with growing demographic pressures, a significant rise in sea levels could turn millions of Egyptians into environmental refugees by the end of the century, according to some climate experts