khamsin

Every spring, usually between March and May, a wall of hot air rises from the Sahara and pushes northeast across Egypt toward the Levant. It carries dust that turns the sky the color of old brass and drops visibility to a few meters while the temperature climbs past forty degrees. The Egyptians called it the khamsin, Arabic for 'fifty,' because tradition held that the wind blows for fifty days of the year. Napoleon's soldiers encountered it during the Egyptian campaign of 1798 and wrote home about it as though it were a judgment.

The Arabic word khamsīn comes from khamsa, meaning 'five,' with the suffix -īn forming the plural for tens, giving fifty. Five is one of the most significant numbers in Arabic and broader Semitic culture: the hamsa hand, the five pillars of Islam, the five books of the Torah. The numeral fifty appears in the wind's name because Coptic Christian communities measured the period from Easter to Pentecost as fifty days, a span that overlaps almost exactly with khamsin season. The wind and the liturgical calendar aligned so precisely that the borrowed number became the word.

Meteorologically, the khamsin belongs to the sirocco family: hot, dry winds that pick up sand crossing desert terrain and arrive at the coast carrying both heat and fine particulate matter. Al-Masudi, writing in the tenth century, described it in his geographical compendium Muruj al-Dhahab, noting its effect on travelers crossing the Egyptian desert. The Ottoman administration that governed Egypt from 1517 used the word in official records of agricultural and commercial disruption. Ancient Egyptians had names for the wind long before Arabic arrived, and the phenomenon appears in Coptic medical texts as a cause of eye complaints and respiratory illness.

English borrowed khamsin in the seventeenth century. The Oxford English Dictionary records its first appearance in an English text in 1676, in a translation of a French traveler's account of Egypt. Variant spellings accumulated over the following two centuries: chamsin, khamseen, hamsin. British soldiers stationed in Egypt during both world wars learned the word from experience rather than dictionaries. Today meteorologists use it as a technical term alongside sirocco and sharav for the category of regional hot winds that move from desert to coast.