Mosques are seen through fog and cold weather in Cairo December 11, 2010. REUTERS/Amr Abdallah Dalsh
Officials at Cairo airport said preventive measures were being taken after visibility was reduced to 300 metres (yards).
Twenty-six ships were barred from entering the Suez Canal and 29 vessels delayed for three hours before they could move through the waterway linking the Mediterranean to the Red Sea.
The waterway was hit by poor visibility and winds of up to 40 knots an hour, said an official at the canal, Egypt's third-largest source of foreign revenue after tourism and remittances from expatriate workers.
High waves also closed all eight of Egypt's main Red Sea ports on Sunday for the second consecutive day, as well its Mediterranean ports of Alexandria and Dekheila, officials said.
Meteorologists said the bad weather was expected to last through Monday and have advised people to stay indoors due to a sandstorm that has blanketed the Egyptian capital.
With temperatures having plunged since Friday night, thunderstorms and heavy rains have lashed the north coast, Red Sea region and the Sinai peninsula.