November to March — the season
Days of 18 to 25°C, cool nights, clear skies and low humidity. This is when to come, without much argument.
December and January are the coolest, and mornings can be genuinely cold — 8 or 10°C — which surprises people who packed for Egypt. Bring a jacket for the evenings.
Rain is rare and light, a handful of days a year, but Cairo’s drainage cannot handle it and streets flood briefly.
This is high season for hotels, though Cairo’s prices remain low by international standards.
April, May and October — the shoulder
Warm to hot, from the high 20s into the 30s. October is excellent. April and May are increasingly uncomfortable as the month goes on.
The khamsin blows in spring, roughly March to May — a hot southerly wind carrying sand, which can raise temperatures sharply and reduce visibility for a day or two at a time. It is the one weather event worth knowing about, and it is not predictable.
June to September — the summer
35 to 42°C, sometimes higher, with strong sun and almost no shade at the archaeological sites. The pyramid plateau, Saqqara and Al-Muizz Street become punishing between about eleven and four.
It is not impossible — Cairo functions, the museums are air-conditioned, and hotel prices fall — but every outdoor plan has to be built around early mornings and evenings. Take it seriously: heat exhaustion at Giza is a routine occurrence.
Cairo’s humidity is lower than the coast’s, which helps.
Ramadan
Moves about eleven days earlier each year, so check it against your dates.
During daylight, most restaurants close, monument hours shorten, and the traffic in the hour before sunset is the worst of the year as the whole city hurries home for iftar.
After sunset, Cairo is transformed. Islamic Cairo and Khan el-Khalili during Ramadan nights — lit, packed with families, open until two in the morning — are the best they ever are.
It is a very good time to come if you plan around the days rather than being caught out by them.
Dates worth knowing
7 January — Coptic Christmas, a public holiday. 25 January — Revolution Day. Sham el-Nessim — the Monday after Coptic Easter, an ancient spring festival predating both Christianity and Islam, when the entire city picnics outdoors. Eid al-Fitr and Eid al-Adha — everything closed or very busy. 23 July — Revolution Day, 1952. 6 October — Armed Forces Day.
The Egyptian weekend is Friday and Saturday.